GO to the Company Gear (upper right hand corner)
- Select “Company Setting” under Settings
- Select “Sales” under Settings (or “Sales Form Entry” under Preferences)
- Check-box “Custom transaction number” (see attached screenshot below for reference)
- SAVE
GO back to create new Invoice
- Click “+” plus sign
- Select “Invoice” under Customers
- Enter new “Invoice no.” (located at top right corner)
Click on the screenshots below to enlarge them
#QuickBooks Online