Once the Custom transaction numbers or the auto numbering function is off in QuickBooks Online, the field will also be removed @chris194.

QuickBooks automatically adds the invoice number in sequential order once saved. This detail and field will be hidden on the invoice page after you turned the feature off.

Customizing the sales forms in QBO is a great way to add and branding to your invoices, receipts, and estimates you send to your constituents. You can create multiple templates in the future and toggle between forms when invoicing a customer.

Should you have other questions about the invoice, just leave a message below. The Community team is always right here to help.