I heard once that sending an email is like posting a letter and leaving the envelope open.
Ie, it’s not very secure.
So, an alternative if you’re working on your computer and want to send passwords or bank details or similar, and WhatsApp isn’t practical for whatever reason, try something that I only heard about a week ago: Privnote.
It lets you send an encrypted note and, when the person at the other has copied what’s inside, the note self-destructs.