Remove permissions from users or groups in the targeted locations.
Prerequisite(s)
You have site collection admin permissions on your targeted site collection(s).
Note: Site collection admin permissions are required even if you have higher admin privileges like SharePoint admin or Global admin permissions. For more info, see Microsoft administrative permissions.
Tip: To manage all your site collections, you can connect to your central admin or admin center with SharePoint admin, Farm admin, or Global admin permissions.
Index
How-to
Select the item you would like to perform the action on from the Explore screen.
Click Remove Permissions from the Quick actions menu.
You will be brought to the options screen.
Verify the targets you are removing permissions from.
Type in the correct user(s) or group(s) (one type or the other, you can't select both users and groups).
Select which permissions to remove from the drop-down (see below for details).
Click Apply.
Once the action is complete, you will see a report with the results (successes, errors, and warnings).
In the case that there are warnings or errors, they will be displayed with details in separate tabs near Results.
Remove permissions (dropdown)
Remove permissions from the selected users or groups by removing them from existing groups, or by removing their explicit permissions.
Remove from existing groups: Allows you to remove the user or groups from a list of existing groups.
Remove from site collection administrators: Removes full control from the selected users to all websites in the target site collection(s).
Remove explicit permissions: Allows you to remove specific permissions from the user or groups (i.e. edit, contribute, read). You can select whether to remove permissions from all subsites, lists, and libraries with unique permissions, from list and library content, or to break inheritance.
Note: Breaking inheritance breaks the permission inheritance for the target objects only if they contain the role(s) you want to remove.Remove all permissions: All explicit permissions will be removed from the selected users or groups, including the built-in and custom permission levels available in the target site(s).
Remove from site collections: The selected users or groups will be completely removed from the target site collection(s).