In some situations it is necessary to zip a file into one smaller file in order to conserve space, keep multiple files in one item or accommodate the University of Windsor CLEW's 50Mb upload limit.
Occasionally zipping a file is refereed to as archiving a file.
Here is how to zip a file
On a PC
Select the files then right click them and select "Send To" > "Compressed (zipped) Folder". Windows will then create a zipped archive with file name of the 'first' file.
On a Mac
Select all of the items then ctrl+click (right click) the files and select "Create Archive of X items". The Same menu can be found under the "actions" menu.