For 2022, Obsidian on iOS and Mac (with PDF Expert for annotating PDFs in my vault).
For all time, Preview.app on macOS, possibly the single greatest advantage Mac has over Windows.
For all time, Preview.app on macOS, possibly the single greatest advantage Mac has over Windows.
The signature feature is awesome - it lets you use a trackpad or iPhone as signature pad, or capture an image. Signatures are saved for future use.
PDF support is really great - things like annotations work well and it supports proper page numbering (e.g. textbooks often have page 1 starting 10 or 20 pages in; Preview handles this) - something that built in options on windows tend to lack.