I routinely check, review, mark up records. I also use the markups to keep track of changes. Word documents are unacceptable because I need to keep a permanent record that work was done.

PDF Exchange editor has a tool that lets me draw a polygon, and set the color blend mode so the polygon acts like a hilighter. I can use this to flag something that is an issue, use different colors to identify the type of issue, and whether or not it has been addressed/resolved.

Adobe acrobat lets me twiddle the opacity, but this makes reading the file difficult, because the opacity interferes with readability.

Can we have a free-form/polygon hilight tool, or adjust the color blend mode of polygons & lines?