Here are step-by-step instructions to highlight PDFs with SumatraPDF:

The other day I read about a hidden text 'annotation' feature available in a prerelease (test) version, and it works nicely to highlight PDF document text as such: My favorite PDF reader of late is Sumatra PDF, a lightweight PDF and ebook reader that doesn't even need installation. Adobe Reader DC (even Edge browser can do it) but as we've seen Adobe reader is rubbish in terms of shell integration and working with xplorer², plus it is slow and resource hungry. There are many PDF reader tools that add text highlighting capabilities, e.g. But what about academic books? Electronic versions of scientific or computer books are convenient (you can easily search in them), but you still miss out underlining and highlighting paragraphs, scribbling explanations, annotations and other such hard-copy operations that help you revise a book. When it comes to timewasting books like novels you read on holidays, e-books are preferable. There are two kinds of people in the world, those that prefer traditional printed books, and those that go for electronic versions thereof (e-books, PDF documents etc). ■ Annotate PDF books using Sumatra PDF reader

Sumatra pdf reader