How to make a 'key-user' the owner of a site?

Question

I'm still new to SharePoint, so maybe this is a easy fix.

There are many sites and people email the SharePoint admins to grant them permission to view/edit a site they think they need access to. This is fine for now but I would want to place this task lower in the organization, because it is difficult for us to determine who should have access to a site and who should not.

I would like for a key-user of a site to be able to manage (add/delete) the members of the specific site. So, this person should be able to invite other people to the site and get an e-mail notification when other non-key-members of the site are trying to share a file or add a member to the site for approval. I could just make them site owner but then they would be able to also edit the look and feel of the site or delete document libraries. And that’s not something we want them to be able to do. How can I best configure this? Thank you for your time :)

EDIT:

We do have the default group called 'members'. I thought it would be sufficient if I just made the key-users the owner of the group 'members'? (you can do this in the group settings panel) and then set up the e-mail notifications for that user. Is that the best way to do it?

(PS: we use SharePoint Online in combination with Office 365)

Answer 1

First of all you should create subsites based on departments or something. Then break permission of subsite. Create custom permission level and configure permissions as per your requirement, atleast they should have manage permissions rights.... Identify key users and give custom permission level to group or individuals.

Regarding your question on groups - that can be one way of doing it, but i think still you would need custom permission level with required permissions to be assigned to this group.