Hi MrRidley!
Let me help you in fixing the invoice file name.
The standard file name when sending an e-invoice is Invoice_xxxxx_from_BusinessName.pdf and this is pre-generated. It's possible that there's an issue with the browser you're using. I have some steps that we can perform to fix this.
Let's start by using an incognito window and send the invoice from there. Second, clearing the cache will since it can also cause issues in QuickBooks Online. Third, make sure that the browser you're using is updated.
Additionally, you'll want to update, repair, or re-install Adobe Reader/Acrobat. QuickBooks Online uses this in generating forms.
Once done, let's try sending the invoice to your self first to see if everything's good. Then, you can resend it to your clients.
I'll be here if you need anything else. Have a great day!
