Zip - file format - was created in 1989.

Right click the file and click "Send to" then click "Compressed Zip File" and select the save location.

The ZIP file format is effective because it allows for files to be temporarily compressed. It also temporary stores multiple files as one file for easy downloading and sharing.

Change the Doc format to . any other format like rich txt format or .TXT format

A zip file is usually in the smallest format possible for a condensed file. If you need for your file to be smaller it might be necessary to try making a zip file from a different vendor who may do something behind the scenes to make the file smaller.