The purpose of the web console is to function much like a normal console, so copy and paste won't work as it would with a terminal emulator, such as PuTTy.
If you want the ability to copy and paste, and you're on Windows 8/10, then PuTTy is one of the best solutions when it comes to keeping things simple, so I'd recommend using it. Of course, there's a bit of a learning curve to it, though once you're setup, you'll be able to quickly login.
The alternative, if you're on a MacBook would be Terminal or Hyper. Both function like the standard emulator that comes with Linux OS's, so you'd use the standard:
... for password based authentication or:
ssh root@IP -i /path/to/private_key
... for SSH Key based authentication.
When it comes to PuTTy, the keys generated by PuTTyGen are not compatible with OpenSSH, but it does provide OpenSSH key conversion and the ability to import a key and get the OpenSSH based key.
When you run PuTTyGen, and a key has been generated, you'll see a box underneath
Key, which is labeled as:
Public key for pasting into OpenSSH authorized_keys file:
The contents of that box are what you'd paste in to the DigitalOcean control panel when adding an SSH key.
The string will start with:
... depending on the type of key you generated (for security, only RSA and ED25519 keys should be used).
You'll then want to click on
Save public key and
Save private key -- store them somewhere that's secure (locally on your PC). We'll use the saved private key here shortly.
Once you've stored the key to DigitalOcean, deploy a Droplet and select it as the key you want to deploy with your Droplet. Let the deployment complete.
Once the Droplet is deployed, run PuTTy. For:
Host Name (or IP address) -- enter your Droplet IP
Port -- 22
Connection type -- SSH
Now, from the left menu, click on
Connection. It'll expand. Now click on
Auth. Find the box at the bottom that's labeled:
Private key file for authentication
Browse and locate the private key you just saved to your PC in the previous step.
Now scroll back up to the top of the left menu and click on
Session. Click on
Save to save the session, then click on
Open to bring up the prompt.
root as the username and from there, you'll either be auto-logged in, or prompted for the passphrase you set on your key.