To add or edit a Tutor's Qualifications, go to People > Tutors > select the Tutor and click Edit next to the 'Qualifications' panel. From there, you can select the Qualification subject and level, the Institution, and the Grade and Year it was achieved.

Adding Qualifications to a Tutor's profile.

You will first need to create these via System > Settings > People and Activity > Custom Subjects and System > Settings > People and Activity > Custom Qualification Levels before they can be added to your Tutor's profile. You can read more about Custom Subjects and Custom Qualification Levels here.