Delegate Administrator is a very important option available in Salesforce which will help Administrator to delegate his/her tasks to selected people thus allowing them to keep focused on few other important areas.

You can –
Manage delegate administrator – if you have “Customize Application” permission. 
Become delegate administrator – if you have “View Setup and Configuration” permission. 
But we should know what a delegate administrator can do –

  1. Create and edit users in a specified role and subordinate roles including password reset, setting quota, creating personal groups for those users,  creating default opportunity team. 
  2. Unlock users. 
  3. Assign users specified roles and permissions. 
  4. Login as user who have granted login access to administrator. 
  5. Manage custom objects. 
To create a delegated group, click Security Controls | Delegated Administration and then click New.