It wont allow me to convert an estimate to an invoice

Thanks for posting to the Community, @Jason11_2 Atkinson.

You may be currently using the QuickBooks Online (QBO) mobile application. I suggest using QBO on a web browser. There you can convert the estimate into an invoice seamlessly.

Here's how:

1. Sign in to your QBO account.
2. Go to Sales and then select Customers.
3. Find the estimate and click Create invoice on the Action column.
4. Click Create invoice.
5. Review the invoice and then Save and close.

I've added an article as your reference on how to add estimates to an invoice: Set up and use estimates.
 

Please let me know if you need further assistance. I'm always here to help. Stay safe!