To authenticate with a remote-host by using your public SSH key to use the ssh-copy-id command. Use the -i flag to specify the public key to copy to the remote- ...
The ssh-copy-id command from OpenSSH might fail if there is no private key file with the same name available, because it tries to login with the specified key.
ssh-copy-id can be used to install your public key in a remote machine's authorized_keys. Could the same command be used to install other users' public keys, ...