Below posts might help, the suggestion  is to mark send/ confirm the invoice

https://www.odoo.com/forum/help-1/during-creation-of-invoices-the-lay-out-of-my-invoices-only-show-proforma-version-17-252799

https://www.odoo.com/forum/help-1/how-can-i-get-a-regular-invoice-instead-of-proforma-invoice-i-am-using-the-free-accounting-module-one-app-251685

Why "Proforma" Shows Up

The "Proforma Invoice" is usually a separate document type used in Odoo when customers request an invoice before actual delivery/payment (often for customs or documentation).

You might be seeing it in:

• Printouts / PDF templates (like on buttons or headers)
• Invoice titles when you preview or print
• Email subjects or templates

Steps to Remove or Change "Proforma Invoice"

Option 1: Remove the "Pro-Forma Invoice" button (from the invoice screen)

If you don’t use it at all:

1. Go to Invoicing → Configuration → Settings
2. Scroll down to Customer Invoices
3. If there's an option like Allow Pro-Forma Invoices, disable it (may depend on version).
4. Otherwise, you can hide it via code (see below).