How to provide access to a domain in Plesk via SFTP using SSH keys instead of passwords?
Generate SSH Keys from the computer you intend to access.
Copy your public key to your clipboard or notepad.
Use Plesk SSH Keys Manager extension to authorize access to the domain:
4.1. Install the extension SSH Keys Manager.
4.2. Go to Domains > example.com > SSH Keys > Add Key.
4.3. Paste your Public Key (*.pub) and press Add button.
SFTP into the server using an FTP client such as FileZilla, or via command line: