I have an early Apple 10.5” with Retina display and OS X 10.9 Mavericks, and I've been trying out several new software apps on macOS, including TextWrangler Best PDF reader for Mac OS X Mojave, and the best option for Mac users who are looking to do research and annotate PDFs for class: Reddit Aug 28, 2022 — I'd say the best PDF reader is Nooks or Pages for Mac, and the best option for Mac users searching for a full-featured, professional app to help organize a large collection of open PDF files. I would not recommend using an app with an interface designed by teenagers (like Google Docs, or PDF Junkie for Mac) Best PDF annotation software. Free, no sign up required. A fantastic open-source application to annotate PDFs. I've had it for almost two years with no problems.