Google’s big Gmail redesign was revealed this past April (with G Suite customers getting the first look). It became default for everyone starting in July. One of the key features, Confidential Mode, is now available for mobile devices, though not everyone is as confident in its ability to keep your data private.
Once you’ve turned on confidential mode for a specific email, you can set an expiration date and passcode so that you can restrict access to the email either in the web interface or via SMS. Recipients of these confidential emails won’t be able to copy, paste, download, print or forward the message, and attachments will be disabled.
That doesn’t stop anyone from taking a screenshot of your message, however. As Google notes, “Although confidential mode helps prevent the recipients from accidentally sharing your email, it doesn’t prevent recipients from taking screenshots or photos of your messages or attachments.
Recipients who have malicious programs on their computer may still be able to copy or download your messages or attachments. This feature isn’t available for G Suite customers at this time.”