The easiest way would be opening the user's email client and having them email the note content to their self. This would ultimately come down to one line of code:
location.href = 'mailto:firstname.lastname@example.org?subject=my_subject&body=body_content'
The technologies you will want to look into are:
- NodeJS - the platform you'll be writing JS in on the server
- ExpressJS - a library for easy setup of a server
- Nodemailer - a library for sending emails
- Fetch - an API for sending requests to a server from a client
Once you figure out how to get your users to write notes on the site, you can use these technologies to send that textual information to your sever, where you'll be signed in to an email service, which you will use to email the formatted information. Then you can do all kinds of fun stuff once you have a server set up, like pushing data to the client on the fly using Socket.IO, a library for realtime messaging between client and server. You could even set up a little chatting system, but that's besides the point.
BTW I also do some work for a church in the way of media (presenting content in-house as well streaming), and some IT and development stuff. Happy Programming!