Now, I also could have selected the enclosing folder, in this case the exercise files folder, and chosen to compress that instead. In this case, I'll just drag a rectangle around 'em and now I can either choose file, compress five items, or alternately I can right click on any of the selected items and choose compress five items from here.
So, to zip up these files, I simply select them all. Word processors are notorious for not being very efficient with the amount of space their files take up. Even if I were only sending a single word processing document, I would probably still compress it, especially if it's a large document. But this doesn't say you shouldn't compress single files. Now I could easily open a new email message and drag all of these files into the message as separate attachments, but you're going to find that compressing multiple files into a single attachment generally results in all the files getting to their destination without corruption or errors much more frequently than sending everything uncompressed as individual attachments. I have here on my desktop the exercise files folder for this course.
Fortunately, Mac OS has the ability to compress files in the most popular compression format, the zip format. Compressing a file does just what it sounds like: it makes the file smaller. When it comes to the web, the file size still matters a lot and is a major determining factor in how long it takes to send and receive a file or whether you can send the file at all. Regardless of the type of file you're sending to someone, if you're using the internet to send the file, whether by email or a web-based sharing service, another habit you should get into is compressing your files before emailing them.