Creating a ZIP file on a Mac is quick and easy, as MacOS contains a built-in utility for compressing or unzipping files.
First, find a file or group of files you want to compress. For a single file, simply right-click it and select Compress [file name].
You will see a ZIP file appear in the same folder as the original, which will still be present.
To compress multiple files into one ZIP file, select them all, then right-click and select Compress X items, with X being the number of highlighted files.
A single Archive file will appear in the folder the originals are in.
HOW TO UNZIP A FILE
Unzipping a ZIP file is about as easy as creating one. Simply right-click the file in question, hover over Open With, and choose Archive Utility (or a third-party unzipping program, if you have one).
MacOS will automatically create a new folder containing the zipped files in the same location as the ZIP file.