How to disable the capability of "creating and editing users???

Hello Admin,
How to disable the capability of "creating and editing users??? to my member users?
I mean, my member's admin they have the capability to add users or creating new users to their account?
And how to limit only their memory storage and bandwidth usage in order not for me to over my limit storage as an owner of the multisite? hope you got my point.

Please advise very much.