In order to allow SSH access without typing the password every time we access we need a RSA keys pair already setup, (this it’s explained in an older post).
Now just copy the public key (by default id_rsa.pub) to the server that we want to access.
Now append the contents of this file to the authorized_keys on the ssh folder
cat id_rsa.pub >> ~/.ssh/authorized_keys
And that’s all just remove the id_rsa.pub file, or not.