In Gmail —
How to: send to a list of people by bcc (blind carbon copy), but in the Salutation, writing
Dear …
with their first names.
For example, in
Bcc: N1, N2, N3, …, Nj, …
The N1 in the 1st name on the list would receive his/her messages as:
Dear N1,
The N1 in the 2nd name on the list would receive his/her messages as:
Dear N2,
The Nj in the jth name would receive his/her messages as:
Dear Nj,
Best Answer
You can solve this with Gmail/Google Sheets add-on called Mail Merge where you can create custom presets which can be further used like:
Video tutorials: