Enable .Net framework 3.5 feature on Windows Server 2012

.Net framework 3.5 feature are not enabled by default on windows server 2012. For enabling them you need to follow below
steps.
Go to Server Manager >> Click on Add roles and features  and click next.
 
Select Role-Based or feature-based installation and go next.
 

Select “Select a server from server pool”
 
Go Next again without selecting any option this time
 
Select “.Net Framework 3.5 Features (Installed) 
 
Click Next. Confirm installation 

After installation process you need to restart the machine.

- Thanks.