Good day, @marsha002.

As of the moment, there's isn't an option to customize and move the Mailing Address box of your check transactions. The steps above can only be applied to your sales transactions such as Invoice, Sales Receipt, and Estimates.

But don't worry, I'll pass along your request to our product developers. This way, they'll consider adding an option to customize the template for your check transactions.

Additionally, you can also visit our QuickBooks Online Blog regularly. From there, you'll be updated with the new features and enhancements that our developers are currently working on.

Know that you can always visit our Help Articles page for QuickBooks Online in case you need some tips and related articles for your future tasks.

If there's anything else that I can help you with, please let me know in the comment section down below. I'll be always around ready to help.