There are many ways to send encrypted messages by email. I use Thunderbird, which has had an encryption plugin since 2003, called Enigmail. It is reasonably simple to setup. Enigmail will prompt you for a password, and you'll better pick a strong one (described here, among other places). Enigmail then lets you publish your public key to special key-servers where it can be found. You can also put it online somewhere. I have my public key here. Have a look - it is good to know what these keys look like! You won't get my private key, though. It is for my eyes only.
I have chosen to use a special email address for my encrypted emails, mats_s@henricson.se. The reason is because I once used my ordinary email address, then by mistake threw away my key. Don't ask me for details - it was so stupid that it still makes me blush, even though it happened 7 years ago.
Now, turn on Enigmail encryption for your email account, and send me an email! I promise to send an encrypted email back, letting you know it works.