Okay so load up Google Maps as you normally would, plot your route (although I think Google Maps only allows a max of 10 via points?)
Once you're happy with it, click Details on the left, in blue writing near the journey time, then it'll show you three icons. An arrow pointing into a phone (send to phone), 3 dots in a < shape and a printer. Click the > dots and copy/paste the link into your email, on here, wherever!
Eg.
https://www.google.co.uk/maps/dir/No...d51.066523!3e0