Configure custom permissions in SharePoint 2013

For more precise control of user access to sites, site collections, and site content, you can configure custom permission levels for your SharePoint 2013 assets. A custom permission level is a set of permissions that you identify and then assign to a specific group of users or to a specific securable object. SharePoint groups and permission levels are defined at the site collection level and are inherited from the parent object by default.
The steps to manage a permission level are performed by using the Site Settings page which is located in the upper-right hand corner of the the SharePoint Central Administration website and is denoted by the gear icon.

Customize an existing permission level

If you define a custom permission level that is closely aligned to an existing default permission level, you can change the default permission level as described in the following procedure.
To customize an existing permission level

1. Verify that you have one of the following administrative credentials:
   
   • You are a member of the Administrators group for the site collection.
     
   • You are a member of the Owners group for the site.
     
   • You have the Manage Permissions permission.
     
2. On the Site Settings page, under Users and Permissions, click Site permissions.
   
3. In the Manage section of the ribbon, click Permission Levels.
   
4. In the list of permission levels, click the name of the permission level that you want to customize.
   
5. In the list of permissions, select or clear the check boxes to add permissions to or remove permissions from the permission level.
   
6. Click Submit.
   

Copy an existing permission level

If the custom permission level that you want resembles an existing default permission level, and you have to use both the default permission level and your custom permission level, you can copy the default permission level, and then change the copy and save it as a new permission level.
To copy an existing permission level

1. Verify that you have one of the following administrative credentials:
   
   • You are a member of the Administrators group for the site collection.
     
   • You are a member of the Owners group for the site.
     
   • You have the Manage Permissions permission.
     
2. On the Site Settings page, under Users and Permissions, click Site permissions.
   
3. In the Manage section of the ribbon, click Permission Levels.
   
4. In the list of permission levels, click the name of the permission level that you want to copy.
   
5. At the bottom of the page, click Copy Permission Level.
   
6. On the Copy Permission Level page, in the Name field, type a name for the new permission level.
   
7. In the Description field, type a description for the new permission level.
   
8. In the list of permissions, select or clear the check boxes to add permissions to or remove permissions from the permission level.
   
9. Click Create.
   

Create a permission level

If there is no permission level similar to the one that you need, you can create one.
To create a permission level

1. Verify that you have one of the following administrative credentials:
   
   • You are a member of the Administrators group for the site collection.
     
   • You are a member of the Owners group for the site.
     
   • You have the Manage Permissions permission.
     
2. On the Site Settings page, under Users and Permissions, click Site permissions.
   
3. In the Manage section of the ribbon, click Permission Levels.
   
4. On the toolbar, click Add a Permission Level.
   
5. On the Add a Permission Level page, in the Name field, type a name for the new permission level.
   
6. In the Description field, type a description of the new permission level.
   
7. In the list of permissions, select the check boxes to add permissions to the permission level.
   
8. Click Create.