The GPG options are accessed by pressing p (which stands for PGP, not GPG, since PGP is much older; in fact, all of the GPG support in mutt is still labeled PGP). This brings up a menu at the bottom of the screen:
(e)ncrypt, (s)ign, sign (a)s, (b)oth, select (m)ic algorithm, or (f)orget it? _ If you want to sign the message, just press s. If you want to encrypt it, press e. To both sign and encrypt, press b.
Sometimes when encrypting e-mail with GPG in mutt, you may see a ****message like this:****
Enter keyID for [email protected]: _
If you see this, it means that mutt doesn't have enough information to determine which key to use. Since mutt uses the e-mail recipient list (the To: and Cc: headers) to determine which encryption keys to use, you may need to add more information to the headers. If your To: header only contains an e-mail address and not a name, try adding the name and putting the e-mail address in after it, just like GPG shows user IDs.
** Espero que isso ajude!
* Além disso, posso sugerir que você pesquise no Thunderbird ? É um ótimo aplicativo de e-mail imo. Apenas adicionando uma pequena sugestão!