How to Add Domain User to Local Administrator Group

As an IT professional we all know the benefit of adding domain user to local admin group of laptop/desktop. In a big organization we can not go desk to desk to perform this activity. We can achieve this by using Restricted Groups.
Finding Restricted Groups is easy but it only works in a domain with Active Directory.
Here how we can achieve this.
GPO -> Computer Configuration -> Windows Settings -> Security Settings -> Restricted Groups
Add desired group (I used “localadmin”) which users are responsible. Now you have two different choices of what you want to do with the group you selected. Either you use “Members of this group” or “This group is a member of”.
Note: Here I have not explained what is “Members of this group” or “This group is a member of” instead I will tell you what to put in these boxes.
In Members of this group – Administrator
In This group is a member of – Administrators

After completing this activity update the group policy on server, it will get updated at client end in some time.
Hopefully you found this quicker than it took me to write it, and your problems are now solved.