How to send me encrypted mail
If you do so, your mail will reach my mail server in encrypted form, but it will be automatically decrypted there and added to my normal in-box. (So this is not true end-to-end encryption, but at least the mail is encrypted from your end all the way to my in-box). Any attachments will be lost, unfortunately.
This setup has several advantages; the most important one is probably that your encrypted mail can reach me even when I only have access to my webmail client (which, of course, again uses an encrypted connection).