In this tutorial, you will learn how to compress #PDF file on Windows, Mac, Android, iPhone or iPad by using a conversion website. Open a web browser and navigate to zamzar.com. Scroll down the page. Click or tap on “Document compressions” and select the “Compress PDF file” option. A new webpage will be opened. Click or tap on the “Choose Files” button and navigate to the PDF file you want to compress. Wait for the file to get compressed and once compressed, click or tap on the “Download” button