I am building application using React, NodeJs, Express and MongoDB. In one part of application user needs to fill some form ( not relevant ) and inside of that form there is an option to upload pdf. I've used react-pdf npm module in React to preview Pdf file when its chosen Now in this red-circled area you can se some sort of a target rectangle which is used to save position for other user where he needs to sign document, now my question is how do I manage to accomplish that task. In what form do I need to save that position and in what way can I create target-rectangle thing like in photo