Step 3: Copy SSH key to server

Now that we have a key, we can transfer it to our server. 
This can be done with ssh-copy-id .
Run: ssh-copy-id <user>@<hostname> and it should just work(TM). 
 If this didn't work, you can manually add the key yourself. 
Print the key in your terminal and copy it: cat ~/.ssh/id_ed25519.pub . 
Connect to your server: ssh <user>@<hostname . 
Edit the authorized-keys file: nano ~/.ssh/authorized_keys . 
Paste what you copied earlier. 
Save and exit. 
 Logout of the server and try logging in again. It should not ask for a password.