So, let's talk about a feature in Preview that I wager many readers are not aware exists: annotating PDF documents. even doodling, actually helps me understand and retain the material being read. True, it's highly unlikely that I will ever go back and refer to my annotations, but the act alone of highlighting, underlining, note-taking, yes. All of the aforementioned in different colors and thicknesses, too. You know – underlining, highlighting, drawing arrows, surrounding important passages with ovals and squares, the occasional marginal notes, and even attaching sticky notes. I am one of those learners who benefits the most from annotating my reading material.

Here on TMO, Melissa Holt and Jim Tanous have covered several features available in Preview, such as 'Filling out PDF Forms with Preview', 'How to Combine Multiple PDFs Using Preview', and 'How to Take Mac OS X Screenshots With Preview.' As we'll see, there is certainly more to say about this gem. However, Preview can do quite a bit more than simply let you view pictures and documents.

Technically, it's a browser/viewer for images and PDF files.

Preview is an application that comes pre-installed on every Mac. Elegant, powerful, unpretentious, highly useful, free.

Preview mac os x annotate add an arrow