You mean e2e? on-disk encryption (ie. "encryption at rest") is basically used by everyone, including gmail and outlook.

You can tell how well I've researched this ;) but yes.

	▲	burnte 4 days ago \| parent [-]
		Indeed. The HTTPS connection is enecrypted, and they TRY to use TLS first when delivering mail, but it will fall back to cleartext easily if the other end doesn't support TLS.