How to digitally sign an email and encrypt it in outlook sending message?

Hello there,
I got to send an email (with an html body but I’ll see that later) with Outlook and I got to sign it (digitally not only adding text at the bottom) and encrypt it before sending.
Does anyone got an idea how to perform this ?
I’ll try to join a print screen to show the buttons.
Many thanks in advance.

Does someone can help me please ? Even saying it is not yet possible … Thanks !