When i delete an invoice it reverts back to an estimate , how do i stop this?

Welcome to the Community, @accounts546.

In QuickBooks Online (QBO), when you delete the invoices, they will be reverted to estimates since the invoice was converted from estimates.

To prevent this from reoccurring, you can simply record a regular invoice transaction instead of making estimates first and converting them to invoices.

Additionally, you'll want to create attractive and professional-looking sales forms and add specific information that matters most to your business: Customise invoices, estimates, and sales receipts in QuickBooks Online.

Please reach out to us if you need help managing your sales transactions in QBO. I'll be here to help. Have a great rest of the day!