Create SSH key. The command below creates a key file named id_ed25519 in your User's folder. You can see this file in your file browser (Windows Explorer) if you navigate to C:\Users\YOUR_USERNAME\.ssh or /home/YOUR_USERNAME/.ssh/ under Linux. (Default name is id_ed25519, you can set this name when executing the command below)
ssh-keygen -t ed25519 -C "your_email@something.com"
Enter passphrase for key