Most of the other note-taking and handwriting apps have a palm protector (software, not hardware) that can be slid up to wherever it is needed, and moved down as you progress down the page.
Penultimate doesn't have that, but it is supposed to recognize that the point of contact of your stylus (or finger) is ABOVE your palm edge/heel.
However, it doesn't work too well for me, and the handwriting keeps getting corrupted by the edge of my palm - and yes, I do have the palm position set correctly.
The other problem is that if I'm resting my palm edge on the screen while I'm writing, and as I progress to the right end of the line, the whole page than tries to move to the right, thinking that my moving palm edge is actually trying to move the "paper". I've been having a play with PU (previous version) on my wife's iPad, as I've switched to Notability until PU goes back to allowing selective sync or no sync, and the ability to select the target notebook. And my previous-version .IPA file was trashed, so I couldn't backgrade my iPad. But my wife still has the older version on hers.
Is there a way to avoid that problem, whereby the app thinks I'm trying to move the page to the right as my hand moves to the right while I'm scribbling along the line? Have I missed a setting somewhere? Or do others have the same problem?