Quick overview of Master PDF editor, another (user-friendly) PDF editor:
>>> completing an old post about editing PDF on Linux <<<
This will only present the most basic features of MasterPDF editor 1.9.25.
Open the PDF you want to edit, here is a basic example of what teachers can give to students and say "simply print it, and you're done!" :
Remove the Black Background, usually it is a picture, select it, and press suppr.
Ooooops, looks like text disappeared?
Use the "text selector tool" :
Now Select with a long click the whole area (ctrl+a doesn't work : it will select both text and non-text objects)
Choose color to fill the selected text:
There is no way to invert colors in that software, but it is easy to export the image, edit it with your favorite image editor and then re-insert it.
As this software doesn't provide a tool to make arrows, make a pool of arrows with another one, and paste them there.
Now we have a Printer-friendly pdf :D