How do I add a hand written invoice

Glad to see you post here on the Community, waynegrimes01.

You can use the QuickBooks Online Mobile app to capture customer's signatures on your sales forms. Here's how:

iOS

1. From the Menu ☰, tap on  Quotes or Invoices.
2. Select an existing transaction, or create a new one.
3. Add any necessary information.
4. Tap on Save.
5. Select Get Signature.
6. Have your customer sign with their finger.
7. Tap on Done.

Android

1. From the Menu ☰, tap on Quotes or Invoices.
2. Select an existing transaction, or create a new one.
3. Add any necessary information.
4. Select Done.
5. Select Get Signature.
6. Have your customer sign with their finger.
7. Tap on Done.

If you wanted to add the paper invoice in QuickBooks Online, you can manually record the transaction as invoice and capture the paper invoice as an attachment or reference. For a more comprehensive steps on how to add attachments, you can check this link Add or delete attachments in QuickBooks Online.

Drop a comment below if you need more help with QuickBooks Online. I'm just around to help you!