Let me help you sort this out, @NoGoodSoftware.

Allow me to share information about converting an estimate to an invoice and printing invoices in QuickBooks Online.                                                                                                                                                                                                                                                                             

To start with, an estimate can be converted into an invoice not a bill. If you're trying to convert an estimate to an invoice, here's how:

1. Go to Sales.
2. Choose All Sales tab.
3. Select a specific estimate.
4. Double-click on the estimate to open it.
5. Click Create Invoice.
6. Enter more details about the invoice.
7. Click Save and Close.

On the other hand, if you're unable to print the invoice you've created,  you can download it to your computer and print it from there. Here's how:

1. Click Sales.
2. Select Invoices tab.
3. Look for the invoice you want to print or download.
4. Click on the Action drop-down arrow.
5. Choose View/Edit.
6. Go to the bottom portion of the screen.
7. Click Print or Preview.
8. Choose Print or Preview.
9. Click the download icon beside the printer icon.

Once completed, check out the downloaded invoice in your Downloads folder and print it from there.

If the issue persists, I'd recommend scheduling a callback with our Customer Care Team. An agent will be able to add you to the affected user's list for this on-going invoicing concern.

Here's how to contact us:

1. Click (?) Help.
2. Select Contact US.
3. Under How can we help?, type in any keyword about your concern.
4. Click Continue.
5. Choose We’ll call you.
6. Enter your information.
7. Hit Call Me.

Let us know here in the Community if you have other concerns about printing your invoices. I'm always here to help.