How do I copy business tax return (both federal and state) that I already paid for from my desktop to my laptop?

are you asking about the program that you used to prepare the business return? if so it must be separately installed on the laptop and it must have the windows operating system installed. there is no way to just copy the program from the desktop to the laptop. if you're asking about the actual return. and the computers are not networked so each can communicate with the other. then you would have to save the data file to a thumb/flash drive and then move the drive to the laptop and copy or move it from the portable drive to wherever you want. 

another way is to e-mail it to yourself as an e-mail attachment. then open your email account on the laptop and download it.