Why are my students receiving my emailed attachment through QuickMail as a Zip file?
The new versions of QuickMail automatically converts the files to zip files for ease of mailing. Opening a zip file is a simple process on any operating system and instructions are easily available for anyone who knows how to use Google. [www.google.com]
If you as the instructor are concerned that the students can’t open the document, you should consider providing the documents on the course page in Moodle instead of using Quickmail to send them, and directing your students' attention to that document.