Notes
With the help of Login Access Policies, you can control which support organizations your users can grant login access to.
If you want administrator to login in as a user, you can enable it from here.
How do I enable login access policies in Salesforce?
- From Setup, enter Login Access Policies in the Quick Find box, then select Login Access Policies.
- To allow admins to log in as any user in the org without first asking them to grant access, enable Administrators Can Log in as Any User.
What permission is required to login as another user in Salesforce?
Profiles: Manage Login Access Policies must be checked.