Changing the Document Number Format
To change the format of the numbers SliQ Invoicing assigns to a new document, e.g. to a new invoice, open the Options dialog by pressing the Options button in the toolbar.
SliQ will then display the Options dialog
Make sure the Document Number Format & Prefixes tab is selected on the Options dialog.
From the dropdown, select the type of number you want to change, e.g. invoice number or purchase order number.
Change the options for the selected number format as desired.