Users with the User Administrator role can create users and manage all aspects of users with some restrictions (see below).
Only on users who are non-admins or in any of the following limited admin roles:
Directory Readers
Guest Inviter
Helpdesk Administrator
Message Center Reader
Reports Reader
User Administrator
Reference:
https://docs.microsoft.com/en-us/azure/active-directory/users-groups-roles/directory-assign-admin-roles#available-roles