What do you mean? Encryption is already built into some platforms, and is behind the scenes so you wouldn't know this sensitive data is actually already being encrypted.
Please be more specific. I don't trust Google or Yahoo to keep my emails secure, which is why I mentioned end to end encryption. I personally use an openmailbox.org account and Evolution mail client, which has built in GPG support. But setting it up (creating/importing/exporting keys, configuring the email client, etc.) tends to be beyond the abilities of tech illiterate people.