Bitcoin was created in 2009 by Satoshi Nakamoto, Bitcoin is the first cryptocurrency and was created to be a way to have a fully decentralized currency.This means that not one single entity can control Bitcoin such as banks or government. Bitcoin is instead run by the network.
People called miners verify each block and either approve or disapprove the change. Anyone from anywhere can be a miner, and it requires a consensus from a majority of the miners to implement a change on the network. Or to deny a transaction. Since there are miners everywhere all over the world, no one person or entity has control over the network.
A cash system
Bitcoin was created to be a peer to peer cash system, But with recent changes to the technology it has now moved away from that and is now looking at high transaction fee's for people to transact with this coin. As a result Bitcoin was 90% of the market cap before 2017 and it now only holds about 30% of the market cap. However Bitcoins core function is still the same. It wants to be a digitized cash system that would become a global currency. Changing the way we use cash systems today, and ultimately changing the way we live.
You can read the white paper on Bitcoin for a more technical explanation on Bitcoin. Click here to read the white paper.