Skim PDF (for OSX)

Skim is a PDF reader and note-taker for OS X. It is designed to help you read and annotate scientific papers in PDF, but is also great for viewing any PDF file.

Capabilities

Highlighting on PDFs with different colors.

Writing text notes on PDFs.

There are more features- but generally this is a good PDF viewer and for notetaking.

References

• https://skim-app.sourceforge.io/