So this one I was stuck on for a few weeks. There is a hidden folder called .ssh. On the command line, you need to be in the home directory (via $cd ~) the go to the .ssh folder by (via $cd .ssh) then list the folders to see ($ls). There is a public key and then a private key. It’s often called id_rsa (private) and id_rsa.pub (public). Then there is a file called known_hosts and known_hosts.old which is where previous ssh keys are stored based on your ssh activities.
If you don’t know what ssh is it’s a secure shell into another computer/server. It’s suppose to be a more secure way for computers to talk to each other.