How do I change data in a field across an array of contacts?

[Max's Dad in Traverse]

I want to be able to change the data in a field across an array of selected
contacts. I can do this easily within the Categories field. How can I do
this in other fields such as User defined?

 

[Brian Tillman]

I want to be able to change the data in a field across an array of
selected contacts. I can do this easily within the Categories field.
How can I do this in other fields such as User defined?

As long as you can group by the field, sure.