When reading PDFs, I would also
- add comments for myself
- review a document and provide suggestions
Therefor, I would like to suggest following tools:
- Replace text: strike-through plus replacement suggestion:

- Text addition:

- Text removal:

- Highlight text and add comment to the highlight:

- "Simple" comment box on an arbitrary place of the PDF:

It would be convenient if each of these were accessible with one or two key strokes
That functionality was available in Acrobat Professional roughly twenty years ago, but was lost over the time. Nowadays, all PDF viewers / editors lost that functionality. It would be good if it came back.
When reading PDFs, I would also
Therefor, I would like to suggest following tools:
It would be convenient if each of these were accessible with one or two key strokes
That functionality was available in Acrobat Professional roughly twenty years ago, but was lost over the time. Nowadays, all PDF viewers / editors lost that functionality. It would be good if it came back.