Thankfully, you can reduce the file size of any PDF if you have a macOS after 'High Sierra'. In this instance, lowering the size of a PDF file on a Mac without sacrificing quality becomes an almost impossible task. This tends to be a problem, especially when you want to send this file via email! Heavy PDFs frequently cause issues since they can surpass the size limit imposed by online email services. The majority of PDF files contain many graphics and photos, making the file size reasonably heavy.