Hey, I'm new to this stuff and have no programming skills whatsoever so dumb it down as much as possible for me.. I need to know how to give permission for others to work on/upload/setup my server (for a native iOS app) without handing over my account information.

Also, with this access what exactly do they have the ability to do and view? And how do I remove them when they are no longer permitted to have access?

Thanks so much anyone who answers!
-Brennan