I cannot convert Estimate to invoice please help

Thanks for your first post, @vmdflooring. I'm here to help ensure you successfully convert your estimate to invoice. 

It could be that you're using the progress invoicing feature, hence you’re getting an error when converting. Let's check your settings. 

Here' how: 

1. Click the Gear icon at the top, then select Accounts and Settings.
2. Choose Sales from the left menu.
3. Go to the Progress Invoicing section.

If it's ON, switch it OFF by clicking the pencil icon. Otherwise, I'd recommend you clear cache and cookies to fix issues when using QuickBooks Online. It'll help you get rid of browser-related issues when working with QuickBooks Online tasks. 

Check out this link to see the newest estimates and invoices makeover in QuickBooks Online for future reference.

I'll be here to help you again if you have other questions about converting an estimate to an invoice. Have a good day!