How do I create user accounts that don't have full admin privileges to the main Owner/Administrator account?

I need to let some website people we'd like to hire have access to our web pages and ONLY our web pages.  I don't want to give them the Administrator login credentials which gives them access to everything including email configurations, DNS records, etc.  I just want to create a user account that I can assign to people who are going to work on the pages on my website and that does not give them any other access.  I'd also like to be able to revoke those credentials when they're done so that those credentials cannot be used by a malicious third party that by one means or another manages to steal them.

Looking at my account controls I don't see any way to do that.