Hello Grzegorz Lecter!
The activity report does not have those fields. Please see image below.
It sounds like you are referring to the Grader Report. The Grader report shows the grades with the names of the students and more. It looks like the following.
If you want custom fields in the Grader report, you can do this in the Grader Report Preferences. See link below.
Changing the Grader Report / Gradebook preferences in Moodle
Other than the grader Report preferences, I am not sure what you are trying to change. If you could give a snapshot or steps to find what you want to change we can help you better. Hope this helps.