If a person has a "paper wallet" how can they transfer BTC to another person. I'm sure there are several ways, but what are they?
Import the private key and transfer to another person, or ask the other person to import the private key and transfer to his another address. In the latter case, before the other person transferred all coins to his own address, both the sender and the receiver can spend the money, and this can be messy so please do this face to face.