This is a couple lesson unit that starts with a Google Slides presentation. Just click the link in the downloadable .pdf file for a View Only link to the file. Go to File then Make a Copy to have it be editable for you and your school.
Also included is a link to my kahoot.it game that goes with the slideshow presentation. Students LOVE trying to best each other in kahoot. I've also got a few other little hidden gems scattered through the presentation including email etiquette articles and a youtube video that helps illustrate the idea of meta message and word choice in email (and really any other writing medium).
At the end are some classroom application ideas. Have your students email their favorite teacher, a local business, your state representative or a veteran. Do peer proofreading. Depending on the speed of your class you may use four to six 45-minute class periods practicing this crucial skill.