How do I create a Mac Mail "Template" email?

Looks like an old topic but nothing posted recently on Mac OS Ventura as far as I can find.

I want to send out an email to multiple individual addresses, each customised to their role etc. The template has images and an attachment.

How can I save a template for re-use. Just saving a draft is no use as it's modified and then deleted once edited and sent. Just cutting and pasting loses some of the information, e.g. Title of Email.

Am I missing something obvious in the menu system?

Thanks in advance,

Don