Hello there, SeeBlu.

If you're trying to email the paid invoice to your customer, you'll just have to open the transaction and then click the Email icon, then select Invoice.

On the Information Missing or Invalid window, enter your customer's email address and then click OK.

On the other hand, if you're trying to edit the message template when emailing the invoice, go to the Preferences window and the change it from there.

Please follow these steps:

1. Go to the Edit menu, then select Preferences.
2. Select Send Forms.
3. Go to the Company Preferences tab.
4. Under the Email Templates row, select Invoices.
5. Click the Edit button.
6. Edit your invoice template on the Edit Email Template window.
7. Select Save.

Feel free to reach out to me if there's anything that I can help.