I have been an advocate for email security, encryption, and a company based out of Switzerland called ProtonMail for a number of years. ProtonMail was founded by a group of CERN engineers to help make encrypted email a simple and user friendly process. Today, they have achieved a major milestone. ProtonMail now has complete PGP interoperability and support. This means you can send and receive PGP encrypted email to PGP users outside of ProtonMail. This also allows those who are the most security minded to have more control over their security and privacy by using an email client of their choice along with the ProtonMail bridge software. To learn more about this you can check out the ProtonMail blog here: https://protonmail.com/blog/address-verification-pgp-support/

To sign up for a ProtonMail email account for free here is the signup form: https://protonmail.com/signup