You can make specific fields in your member data read-only, so that members cannot edit those fields.
Admins with Role MEMBERS can edit all fields in member data.
Edit or create a Configuration Item with varname = MEMBER_READONLY.
In the Value field, enter the names of the fields to be read-only, comma separated. Here’s a sample (hint, click on the image below to enlarge).

To find the correct field names, download (some of) your member data. download here, click on the Download tab, select:

The first row has fieldnames.