open terminal and enter below command

ssh-keygen -t rsa

Follow prompt to provide passphrase and destination to store private, public keys.

It creates two files

  • ssh_key
  • ssh_key.pub

Use public key(*.pub content) to create Virtual Machine as in below link..

https://azure.microsoft.com/en-us/documentation/articles/virtual-machines-linux-quick-create-portal/

Login to machine using ssh_key file

ssh -i ssh_key prashanthmadi@104.210.151.66

Enter passphrase to finish login process...