Configuring user's name and email

Name
git config --global user.name "[Name]"

Email
git config --global user.email "[Email"

Signing git commits with SSH keys

Configure git to use SSH for signing.
git config --global gpg.format ssh

Specify the public key to use as the signing key.
git config --global user.signingkey [key location]

Tell git to sign with the key every time.
git config --global commit.gpgSign true