PDF Notes S (universal app for iPhone & iPad)
On March 22, 2019, I uploaded version 12.1.12 of PDF Notes S to App Store and it became Waiting for Review. After Apple finishes its review, it will be Ready for Sale.
App Store https://itunes.apple.com/app/id961336139
This version fixed bugs, and supports 8 configurable writing tools including pen, highlighter, sticky notes, text, text highlight, text strikeout, text underline, square, circle, line.
It also supports more keyboard commands including tab, shift-tab, undo(command-z), redo(shift-command-z).
And there are many other enhancements...