Is there a way to change the thickness and other properties of the PEN tool in Acrobat using iPad Pro w/ pen? I cannot seem to bring up any sort of menu or adjustments for this.
I assume you are referring to the thickness of the Drawing Tool in Adobe Acrobat Reader mobile application?
Yes, you can change the thickness of the tool.
2- Once you have saved, just tap on the drawing that you have done.
3- Options will come up as Delete> Thickness> Color> Opacity
4- Select Thickness > (0.5pt, 1pt, 3pt, 5pt, 7pt, 9pt, 11,pt)> Save
5- The particular thickness will be set as default.