This may not work for everyone. If I must email documents that I do not wish Google to see, I call the person and say "The password to that 7-zip file is fartb

This may not work for everyone. If I must email documents that I do not wish Google to see, I call the person and say "The password to that 7-zip file is fartbubble, all one word, lower-case." I can put a text file in the .7z file that has additional context that would have been in the email body.