Does anyone know how to add a signature to an email on a MAC?

I created a signature in mail preferences, but when I author an email the signature box only gives me one option: None.

choose Preferences from the Mail application menu and click Signatures

select the signature you created and drag it to your account

to add the signature automatically to every message, choose it from the Select Signature pop-up menu.

to choose a signature when you compose a message, select “Choose signature when composing email”.

What is an “account” ? Nothing on my screen says “account” to drag anything to.

It won’t have the word account, it will have whatever you named the email account, probably NACHI or something.