How to send a confidential message on Gmail

Confidential mode on Gmail is pretty handy—I used it recently when I had to send some sensitive tax documents to my accountant. It lets you set an expiration date for the email, and you can even require a passcode to open it, which gave me peace of mind. It’s super simple to use: just compose your email, click on the lock icon, and set your preferences.

Have you tried any other email security features or add-ins that you’d recommend?