Step 1:

$ ssh-keygen -t rsa -b 4096 -C "your_email@example.com" -f /d/key            //to save in d drive
Step 2:

 #start the ssh-agent in the background
$ eval $(ssh-agent -s)

3.Step 3:

Copy text from key.pub and paste into "New ssh Key " at https://github.com/settings/keys