Hello @gmorgan88, welcome to the Community. I'm so glad you are here!

The information on how to add another field hasn't changed.

Is it possible that you have reached a maximum of 3 additional fields to add to your invoice?

If you uncheck any field that you no longer wish to use, it will free up space for you to add the phone number.

Try that, and let me know how it goes.

If you have any additional questions I'm happy to answer those as well!