[*]"roughen" it (ie it adds intermediate points and moves them slightly out of line by a random distance); or
[*]"zigzag" it (the intermediate points are uniformly spaced).
It's based on the ROUGHEN.LSP tool for AutoCAD by Mark Middlebrook. There's a much more complex line tool posted by @TBS that does all this tool can do, and more, here: viewtopic.php?t=48946
Usage
First select the line you want to roughen, then select the tool. For the Ribbon UI it's on the Home ribbon at the right side. For the Classic Toolbars it's in Tools > Add-in Tools > Roughen It will show a dialog
- Type is either Roughen (offset and spacing is random) or Zigzag (offset and spacing is uniform).
Period is the approximate length of the segments (in points) to break the line into.
Amplitude is the maximum distance (in points) away from the line to move intermediate points.
Keep Roughening, if checked, will split up line segments on a selected polyline even if they are shorter than Roughness Period.
Smooth will smoothen the line to make curved patterns
Squareness is what percent of the Period to make the length of each tip on a zigzag (ie zero makes a point, and 100 makes a square wave. It can be positive or negative, and greater than 100%: Preview shows the result of the current values on the output line.
After you press 'OK' it will roughen the line(s). If you've selected a line, it will convert it into a polyline. Installation
Extract (unzip) the zip file and save the files into the JavaScript folder (either in %APPDATA%\Tracker Software\PDFXEditor\3.0\JavaScripts or in the application folder). After restarting PDF XChange it will add a menu item "Roughen" to the Comment Tools ribbon and to the Comment menu (in the classic UI)