Sales entities

Sales entities (your invoicing companies) are the legal sellers that issue your invoices. Each one holds the seller details printed on documents, its bank accounts, its invoice numbering, its logo and its VAT settings. A Polish entity also holds its settings for the EU One-Stop Shop (OSS) scheme and its connection to KSeF (Poland's national e-invoicing system). You need at least one entity before you can create an invoice. You can have several.

Where to find it: Finance → Sales entities. The screen itself is titled Finance setup.

When you'll use it

• Setting up invoicing for the first time.
• Invoicing from a second company in the same workspace.
• Changing a bank account, a logo or the seller's address.
• Choosing how invoice numbers look, or continuing the numbering from your previous program.
• Setting the VAT rate used when a line has none, or the default basis for VAT exemption.

Key concepts

• A sales entity is not a customer. Your customers and suppliers are the Entities (customers & suppliers) under Sales. A sales entity is you, the seller.
• One entity per tax ID. Numbering follows the seller's tax number, so two entities cannot share one.
• The default entity is pre-selected on every new invoice. Marking another one as default takes the mark off the previous one.
• The country matters. Only an entity whose country is Poland gets the registry lookup, the KSeF connection, the OSS settings, cash accounting and the exchange-rate rule for foreign-currency invoices. The country also sets the starting value of Default VAT rate (%).
• Issued invoices keep what they were issued with. The seller's details, the bank account and the logo are copied onto an invoice when it is issued. Editing the entity afterwards changes drafts and future invoices only.

How numbering works

Each entity numbers invoices, corrections and pro formas separately. For each type you choose a prefix and a number format:

Number format	Counter restarts	Example
Year / number (yearly reset)	Every year	FV/2026/0001
Year / number with dashes (yearly reset)	Every year	FV-2026-0001
Year / month / number (monthly reset)	Every month	FV/2026/10/0001
Continuous numbering (no reset)	Never	FV/000001

A new entity starts with the prefixes FV (invoice), KOR (correction) and PRO (pro forma) and the year / month / number format. An entity can also carry a format of its own, for example one taken over from another program. The list then shows Format saved in the entity. If such a format cannot produce unique numbers, the entity page says what is missing.

Invoices and corrections have more than one series:

• Prefix for companies and Prefix for individuals — documents for individual customers are numbered in a series of their own. Until you type your own individual prefix, it is the company prefix with /B2C added (FV/B2C).
• Prefix for OSS — only for a Polish entity with OSS. Documents under the OSS scheme have their own series. Until you type your own, it is the company prefix with /OSS added (FV/OSS).

Every series on an entity needs a different prefix. A prefix cannot start with DEMO.

Rules that keep the numbering continuous:

• A number is assigned when an invoice is issued, not when the draft is created.
• The next number is the highest existing number in the series plus one. So after reverting or deleting the newest invoice, the next one takes its number.
• Once a document of a given type has been issued in the current period, the format for that type is locked until the next period. The period is the year or the month, depending on the format.
• With continuous numbering there is no next period. Once a document of that type has been issued, its format and prefix stay locked.

The screen

📷 Screenshot to add: the Finance setup list with two entities, one marked Default

The list shows one row per entity:

Column	What it shows
Name	The entity name, with a Default mark on the default one
Tax ID	The seller's tax number
Country	The entity's country
KSeF configuration	Shown only when your company has at least one entity in Poland. The value says whether the entity is connected and in which environment. A non-Polish entity shows a dash.
Default currency	The currency new invoices start in
Active	Whether the entity is active

The header has Refresh and New entity. Click a row to open the entity.

The entity page shows the entity's data, its bank accounts, its VAT settings and its Invoice numbering, with a sample number for each series. Next to each series, Change next number lets you move the counter forward. For a Polish entity the page also shows the OSS section and KSeF integration. The header has Refresh, Edit and Delete.

The form (New entity and Edit) has these sections:

Section	Fields
Basic data	Country, Tax ID, Name and Default currency (all required), EU VAT, Registration no., Default VAT rate (%), Default entity
Registered address	Street and number, Postal code, City
Contact	Email, Phone
Bank accounts	One card per account: Account number / IBAN, Bank name, SWIFT / BIC, Currency, Default
Invoice numbering	For Invoice, Correction and Proforma: the prefixes, Number format and the previews
VAT on invoices	Exemption basis type and Basis for VAT exemption. For a Polish entity also Cash accounting.
Sales to consumers in other EU countries	Polish entities only. The OSS settings. See OSS returns.
KSeF integration	Polish entities only. On a new entity it says you will configure it after saving.
Invoice logo	Upload logo / Remove logo

Common tasks

Create a sales entity

1. Go to Finance → Sales entities and click New entity.
2. Choose the Country and type the Tax ID. The form starts with your company's country and currency.
3. For a Polish entity, click Registry next to the tax ID. This fills in the name, address, registration number and EU VAT number from the Polish business registry.
4. Fill in the Name and the address. Check the Default currency and the Default VAT rate (%).
5. Under Bank accounts, click Add account and add at least one account. See Add or change a bank account.
6. Under Invoice numbering, adjust the prefixes and formats if the defaults do not suit you. The previews show what a number will look like.
7. If you sell exempt goods or services, fill in the default exemption basis under VAT on invoices.
8. Upload a logo if you want one on your invoices.
9. Click Save. The entity's page opens.

For a Polish entity, continue with KSeF and, if you sell to consumers in other EU countries, with OSS.

Saving the first Polish entity also makes Finance → OSS returns appear in the menu, and the KSeF permissions appear in the role editor.

Add or change a bank account

1. Open the entity, click Edit, and go to Bank accounts.
2. Click Add account, or change an existing card.
3. Type the Account number / IBAN. It is formatted in groups of four and checked as you type, and again when you save. What is accepted depends on the entity's country:
   • A country that uses IBAN: the number must be a valid IBAN. A Polish entity may also type the 26-digit account number without the PL prefix.
   • A country that does not use IBAN: the number must be 5 to 34 letters and digits.
4. Check the Bank name and SWIFT / BIC:
   • When Complaia recognises the bank from the account number, it suggests both. Confirm the suggestion by ticking the box under it before saving.
   • If you had typed a different bank yourself, the dialog Different bank from account number lets you Replace with account data or Keep mine.
5. Choose the account's Currency.
6. Click Default on the account that should be pre-selected on new invoices. Exactly one account is the default.
7. Click Save.

An entity must always have at least one bank account. An invoice paid by bank transfer cannot be issued without one.

Set up numbering

1. Open the entity and click Edit.
2. In Invoice numbering, set the prefixes for each document type.
3. Choose the Number format. Each option shows an example with your prefix.
4. Check the previews.
5. Click Save.

Do this before you issue the first document of the period. After that, the fields for that type are locked until the next period.

Continue the numbering from another program

Use this when you start using Complaia in the middle of a period and your previous program has already issued numbers.

1. Open the entity. In Invoice numbering, click Change next number next to the series.
2. Type the Next number. The dialog shows the number the next document will get and the highest number already used in this period.
3. If your previous program still issues documents for the previous period, use the switch for the previous period.
4. Save.

The number can only be moved forward, and only in the current or the previous period. Documents of this series with lower numbers can no longer be reverted to draft or deleted, because their numbers cannot return to the series.

Upload a logo

1. Open the entity and click Edit.
2. In Invoice logo, click Upload logo and choose a file: PNG, JPEG, WEBP or HEIC, up to 5 MB. It is scaled to fit 600×300 px.

On an existing entity, a new logo is saved as soon as you confirm the file, and Remove logo removes it at once. Neither waits for Save. On a new entity, the logo is uploaded when you save the entity.

The logo is printed on the invoice PDF. Invoices already issued keep the logo they were issued with.

Change the default VAT rate

1. Open the entity and click Edit.
2. Type the rate in Default VAT rate (%), with up to two decimals.
3. Click Save.

If you clear the field, the country's standard rate is used. What the rate is used for is explained on VAT on invoices.

Delete a sales entity

1. Open the entity and click Delete.
2. Confirm Delete entity?

An entity that has any numbered document cannot be deleted, because the numbering of a tax ID must stay continuous. Update the entity's details instead. An entity with only drafts, or with no documents, can be deleted.

For a Polish entity connected to KSeF, the dialog warns that deleting removes the certificate only from Complaia. In KSeF it stays active. To revoke it, disconnect the entity first. See KSeF.

When it doesn't work

What you see	Why	What to do
Fill in the required fields: …	Name, Tax ID or Country is empty.	Fill in the fields named in the message.
The sales entity has an invalid tax ID.	The entity is in Poland and the tax number is not a valid Polish one.	Correct the number.
A message that one tax ID can have only one sales entity	Another entity already uses this tax ID.	Open the existing entity and edit it.
Add at least one bank account for the entity.	The bank account list is empty.	Click Add account.
Invalid IBAN number. / Invalid IBAN for bank account no. …	The account number fails the IBAN check.	Type it again and check for a missing or swapped digit.
Confirm the verification of the suggested bank name and SWIFT/BIC (tick the consent).	A suggested bank name or SWIFT was not confirmed.	Check the suggestion with your bank and tick the box.
Prefix “…” is used by two series.	Two series on this entity have the same prefix.	Give each series its own prefix.
A message that a number cannot start with “DEMO”	That prefix marks invoices issued on the KSeF demo environment.	Choose another prefix.
Numbering locked: invoices of this type were already issued in the current period.	You changed a locked format or prefix.	Wait for the next period, then change it before issuing.
A message that the next number must be greater than …	Numbers up to that one are already used in the series.	Type a higher number.
Unsupported format. Allowed: PNG, JPG, WEBP, HEIC. / File is too large (max 5 MB).	The logo file is not accepted.	Use a supported, smaller file.
A message that an entity with issued invoices cannot be deleted	The entity has numbered documents.	Keep it and update its details.
Company not found. Fill in the details manually.	The registry returned nothing for the tax ID.	Type the details yourself.

Permissions

To do this	You need
Open Finance → Sales entities; create, edit and delete entities; upload a logo; change the next number; use the registry lookup	Finance: settings
Choose a seller on an invoice	Finance: View
Upload, test, revoke or remove a KSeF certificate	Finance: KSeF configuration

The built-in Accountant role includes Finance: settings but not Finance: KSeF configuration.

Related

• Invoicing — where the entity is chosen as the seller, and how the series work
• VAT on invoices — what Default VAT rate (%) and the exemption basis are used for
• KSeF — connecting a Polish entity
• OSS returns — OSS settings of a Polish entity
• Company details — your own company in the workspace, which is separate from sales entities
• Glossary — sales entities versus customer and supplier entities