First check existing SSH keys1
ls -al ~/.ssh
Then generate one, if necesary1
ssh-keygen -t rsa -b 4096 -C "siddhantrimal@hotmail.com"
to store this in the global context, provide this filepath:
/c/Users/Siddhant/.ssh/id_rsa
Copy the SSH key to clipboard2
clip < ~/.ssh/id_rsa.pub
Now login to your github account and, while logged in, open this link https://github.com/settings/keys
on the next tab and paste the key from your clipboard. Henceforth, use the SSH address of your repository to use it.