Do you have a field value per column? If that's the case, then just rename the field by double clicking on it in the Visualizations pane. If it's a single column and the matrix splits it, then just create a custom/conditional column either on Power Query or DAX whee you specify that IF Column = 1 then "Name Of The Group".
Did I answer your question? Give your kudos and mark my post as a solution!
Proud to be a Super User!
Helpful resources
Power BI Monthly Update - September 2025
Check out the September 2025 Power BI update to learn about new features.
Fabric Community Update - August 2025
Find out what's new and trending in the Fabric community.
