Account management

Hello, F1.

Good to see you here in the Community. I can help ensure you're able to add your phone number on the basic invoice in QuickBooks Desktop (QBDT). 

You can create an email template to add your new phone number or other information that you want to include on the basic invoice cover.

Let me walk you through the steps:

1. At the top menu bar, select Edit.
2. Go to Preferences...
3. Choose Send Forms.
4. Click Company Preferences.
5. Select Add template. 
6. On the Add Email Template, fill in the necessary information.
7. Make sure to mark the template as Default. 
8. Click Save, then OK.

For additional reference, you can always check this article to learn more on how to use and customize form templates. 

This should get you on the right track. Feel free to leave a comment below if you have any other concerns about adding email template. Have a great day ahead.