Folks don't know if this is even possible, with Acymailer or even anything, just blue skying here, is it possible to create a template email primarily for Outlook (that can behave when send and forwarded and replied) that can be saved and texted entered by the end user. I'm using Joomla version.
AcyMailing provides a way to create a template and use it for all future emails, if that is what you are asking for
Nope, this would be a template that the end user has and they can manipulate, nothing crazy change text, very limited editing, usual constraints of a email engine. If you remember Apple Mail has something like this called 'Stationery' but they binned it, it was quite buggy IMHO. https://itstillworks.com/make-stationery-mac-mail-9555.html
I am sorry, but this sounds exactly as a template which you prepare and your users, who will be sending newsletter, can then additionally adjust, change the text and send it away to the newsletter list subscribers