Configure numbering and document series

Go to Settings - Template design and settings - Numbering

Find the section for the document type you want to configure (invoices, estimates, delivery notes, etc.)

Choose a predefined format or enter your own custom format

Set the Next document number to control what number the next new document will receive

Save

Use YY or YYYY for the current year

Use NN, NNN, or NNNN for the sequential number

Format NNN → 001, 002, 003

Format YYYYNNN → 2025001, 2025002, 2025003

Format INV-YYYYNNNN with next number 580 → INV-20250580, INV-20250581...

Each business in your Billdu account has its own separate numbering

There is only one numbering sequence per business

If you manually edit the number on a document while creating it, the automatic sequence is interrupted for that document only - it does not affect the overall sequence in Settings

Changing a number directly on an existing invoice does not affect the overall numbering