Hi @Milan_Vucetic I would say its pretty straightforward if you are creating the emails yourself in a code library like JavaMail where you can just add new Mime Body Part to the email. I dont think it would be that easy in Campaign as the UI is tightly coupled to HTML-only, Text-only or Multipart-alternative HTML+Text delivery options.
It looks like Adobe implemented (beta only) an email part for AMP content, so I expect you would need to do something similar for watch-html type to get it added and sent inside your multipart-type email.
