Run the command:
ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/milo/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/milo/.ssh/id_rsa.
Your public key has been saved in /home/milo/.ssh/id_rsa.pub.
The key fingerprint is:
The command ssh-keygen -t rsa initiated the creation of the key pair.
No passphrase was entered (Enter key was pressed instead).
The private key is saved in .ssh/id_rsa. This file is read-only and only for you. No one else must see the content of that file, as it is used to decrypt all correspondence encrypted with the public key.
The public key is save in .ssh/id_rsa.pub.
Copy the content of the public key to .ssh/authorized_keys of the system you wish to SSH to without being prompted for a password.