By default, a team leader can only request feedback from someone about their own team members. As an admin, you can also give team leaders the ability to request feedback about someone outside their team.
To enable this setting, first navigate to Studio > Feedback.
You will now see the feedback settings screen. In the section 'Visibilities for Feedback and Feedback Requests', you will see the option “Allow team leaders to request feedback for”. You can change this setting to the option “All people” to allow team leaders to request feedback about any user on the platform. After doing that, click on the “Save changes” button at the top of the screen.