I use the freehand markup tool a lot with Apple Pencil and iPad Pro. The palm rejection doesn't always work and I tend to use an art glove to keep from making stray lines. The issue is that sometimes the strays commit with the rest of the markup and you can't select and delete them separately. A pencil really needs an eraser. Please add one.
Thanks,
Jean-Frederic Monod
Open Workshop for Architecture, Tampa.