

Get your own domain and use that with Proton so you can take your email address to whatever email provider you want, or host your own. In the future, switching won’t be nearly as hard since you’ll just need to redirect the domain to the new email provider instead of changing your email address with everyone, again.
@pound_heap
When you send an encrypted email to a non-Proton user, you click on the lock icon to encrypt the email and assign it a password, which you need to get to your user. The recipient then receives an email with a link. They click on the link, enter the password and and can then view your email, which to my understanding is decrypted client-side.
https://proton.me/support/password-protected-emails
@zerodawn