All the answers I see here are just confusing me. What is a ‘ client ‘? Is it me, my computer, my online wallet, the person selling to me or buying my bit coin or what ? I just want to know how to send bitcoin from paper wallet to online, to spend, and what to do to avoid losing the change remaining in the paper wallet. I GUESS it is like this…empty the paper wallet to an online wallet. Pay the other party by sending off bitcoin. Then make a new online wallet – must I ? Put the remainder bitcoin in there Make a new paper wallet.Send remaining coin back to new paper wallet. Sounds simple? But I have NO IDEA about how to use the private and public keys. Do I have to make a new private key for every step in the above ?