Hi userleanadeklerk1412!
Security is one of our priorities. Let me show you how the invoicing in QuickBooks Online works.
Although you have an option to either attach a PDF file or not when sending an invoice, once they click the Print or save button on the email, they'll still be routed to a page where they can download a PDF copy. Once downloaded, they can edit, add comments or text using a PDF editor like Adobe Acrobat.
However, they won't be able to make any changes to the content of the email. They can't edit the details showing when clicking the Print or save button.
You'll want to turn on the option to receive a copy of the email for future reference. Here's how:
- Go to the Gear icon and select Account and settings.
- From the Sales tab, select the Messages section.
- Check the Email me a copy box. Tap Save, then Done.
I've added these links for the detailed steps on how to create and personalise an invoice:
Feel free to post again here if you need more help. We'll respond as soon as we can.
