Using some free online PDF converter can work well on any OS, including Windows, Mac and Linux. Below I will show you an effective way to help you reduce your PDF size on Mac. The Online Compress PDF Tool will provide you with five modes. You can select one from them according to your requirement. Step 1. Launch EasePDF. To reduce PDF size, click on "Compress PDF" tool. Step 2. Now you can upload your PDF file. You can upload PDF from your local computer, or Google Dvire, Dropbox and OneDrive. Also, directly drag and drop your file into the table is acceptable. Step 3. Select the mode that you want in the menu below. Step 4. Now please wait a few seconds for the compression. When itâs done, you can save it to your local computer, or to save it to Google Drive and Dropbox.