At CHA we use Virtru to encrypt emails with sensitive information. To use Virtru you need to install the extension
Chrome Web Store for Virtru extension: https://chrome.google.com/webstore/detail/virtru-email-protection/nemmanchfojaehgkbgcfmdiidbopakpp (other browsers would have their own app/addon stores which would also work)
After installing Virtru you can send an encrypted email by sliding the Virtru encryption to "On"
If a recipient does not have Virtru installed, they can still access the encrypted email through Virtru's Secure Reader. : https://support.virtru.com/hc/en-us/articles/115012284147-Read-a-Virtru-Encrypted-Email-without-Virtru-Installed
They can still open the message after verifying their account, the app isn't required - this makes sure that things aren't just forwarded along to an unintended recipient