Administrators and owners of SharePoint list, library or survey can change permission for letting the selected people access the required data and restrict others from accessing them. All the sites, lists, libraries and surveys in a site group get their permission settings from the site that lies immediately on top of them in the hierarchy. For editing and managing permissions to a list, library or survey, you must first break the permissions inheritance. This can be done on the Permissions page.
Here we learn how to land on the permissions page, break inheritance and follow through the steps necessary to edit or change permissions.
How to view the permissions page in SharePoint Online, 2013 and 2016
Open the library or list or survey, choose settings and then click on Library settings or List settings or Survey settings. If you do not see Settings, choose the Library, list or survey tab and then click on Library settings or List settings or Survey settings.
Under Permissions and Management, click on Permissions for this list or Permissions for this document Library or Permissions for the survey as is the case may be.
Managing unique permissions for individual items
Some items in the list might have been assigned unique permissions which cannot be controlled from this page. To know what are in the list of unique permissions, click on Show these items and you will find an Exceptions dialogue box listing out the items under this category. For making changes, click on Manage permissions for each of these items to make the changes as needed.
Managing limited access user permissions
The site can also have some limited access users in cases where some users have restricted access when an item is shared with them. To see who are having limited or restricted access to some items, click on Show users. When you unshared the item, the user will only have limited access to the site and cannot access the items not shared with them.
How to break permissions inheritance
If you see the message, “This library inherits permissions from its parent”, this will mean the inheritance for the list, library or survey is not yet broken. To break permissions, follow these steps.
Open the list, library or survey
Go to the permissions page
Click on Stop inheriting permissions to break permissions
How to assign unique permissions in SharePoint Online 2013, 2016
First, you must break the permission inheritance from the parent site to be able to grant unique permissions. After breaking the inheritance by following the steps in the above section, go with these steps to assign unique permissions.
Open the list, library or survey
Click on Grant permissions on the Permissions tab
In the Share dialogue box, ensure that Invite People is selected. Go to the Enter names or email addresses box and type the names of the people or group you wish to provide access to.
If you want, you can also add a personal message.
You can now check or uncheck Share everything in this folder. This can also be done for items that have unique permissions. This can grant or restrict aces to those items for which you have already set unique permissions. All those people who are given access can make changes to the list, library or survey. If you wish to change permissions level like Read-only, click on show options and change the selection in the Select a permission level box. An automated email will be forwarded to all those in the Invite people box. If you do not want to send these automated emails, you can click on Show options and uncheck the Send an email invitation.
Once you finish these steps, you can click on Share.