Is it enough to use VPN\TOR+GMail to keep the sender anonymous?

Question

Information Security

The task is to ensure the anonymity of the sender of the mail.
Used by Gmail through the web interface (the account, of course, does not contain reliable personal information).
1. Is it enough to use a VPN for this?
2. Is TOR sufficient for these purposes?
What other points should be taken into account to maintain anonymity (do not do anything on the computer, or, on the contrary, do something)?