GoodNotes

GoodNotes is a popular digital notebook app for iPad, Mac, and iPhone, known for its realistic writing feel and excellent PDF annotation. It features powerful handwriting search and organization into digital notebooks. It supports shapes, typed text, and images. It's a favorite among students for note-taking and professionals for annotating documents.

It uses a one-time purchase model. It ranks as a top-tier tool for knowledge management centered around handwritten notes and PDFs, offering a superior paperless experience.