Bitcoin is a cryptocurrency. It means that it's an encrypted and shared form of money made by building links in a blockchain code. Blockchain records all Bitcoin transactions on computers of volunteers across the globe. Those computers run software that verifies the transactions and makes sure that they are valid. It's called mining and these volunteers receive some percentage of the currency as a kickback. Once enough computers confirm the exchange as valid, it creates a "block" that's added to the rest of the world's transactions.