Hi,

I'm an engineer from Quickbooks Online team. 

Thanks very much for reporting the issue.  What you're seeing is a bug. This image was intended for a different screen. Due to the bug, in certain flows, the "Create Invoice" button on the estimate screen got replaced by this image.

This issue has been fixed and got released today. Upon your next login, the "Create Invoice" button should be visible as it used to be.

Thanks,

Thiyagaraj