You can update the default document number for Invoices, Quotes and Orders.
Open the document and hover over the document number at the top of the screen. Click the pencil icon to edit.
The document number must be unique and contain no more than 30 characters, including numbers, letters and dashes ("-").
Once your changes are made, click "Save" to update the number or "Cancel" to leave the edit mode without making changes.
A document number can be edited until the document is sent or linked. For example, if you create an Order from a Quote, the Quote number can't be edited. However, you can edit the Order number until you send an Order or create an Invoice.
Editing the Order number will change the Purchase Order number, but will not change numbers for newly created linked transactions. Those document numbers are generated based on your standard Document Number settings.