Has anyone had issues with PDF invoices sent from QuickBooks Online (mostly Gmail) being flagged as malware, and if so, did you find a solution to correct the problem?

I appreciate all your efforts in dealing with this, @greg153. I'll point you in the right direction to address the Virus Detected issue when attaching a PDF copy of an invoice in Gmail.

Here's how:

1. Go to Help.
2. Select the Search tab, then choose Contact Us.
3. Type in your issue or concern in the field.
4. Hit Continue.
5. Click the Chat or Callback option.

You can contact us from Mondays to Fridays, 6 AM to 6 PM PT, and Saturdays, 6 AM to 3 PM PT.

I'll add this resource to learn how to process customer payments and to mark the invoice paid: Record invoice payments.

We'll be around to help you if you have any other concerns about invoices.