SHELL

ssh-add git

$ eval "$(ssh-agent -s)"
$ ssh-add -K ~/.ssh/id_ed25519

terminal git add ssh key

$ ssh-add ~/.ssh/id_rsa

git add ssh key

To add a default ssh key tied to Windows from cmd for git: $ is things you type, > is output

$ ssh-keygen 
> Generating public/private rsa key pair.
> Enter file in which to save the key (/c/Users/emmap1/.ssh/id_rsa):    [Enter for default] 
> Created directory '/c/Users/emmap1/.ssh'.
$ Enter passphrase (empty for no passphrase): [password]
$ Enter same passphrase again:  [password]
> Your identification has been saved in /c/Users/emmap1/.ssh/id_rsa.
> Your public key has been saved in /c/Users/emmap1/.ssh/id_rsa.pub.
> The key fingerprint is: e7:94:d1:a3:02:ee:38:6e:a4:5e:26:a3:a9:f4:95:d4 emmap1@EMMA-PC

If you want to avoid typing in your password each time:
$ start-ssh-agent
> Removing old ssh-agent sockets
> Starting ssh-agent:  done
$ Enter passphrase for /c/Users/user/.ssh/id_rsa: [password]

git add remote via ssh

git remote add origin ssh://user@host/srv/git/example