Bitcoin is a new form of money that is completely independent of centralized companies (banks, governments, etc.). It was created back in 2008 during the financial crisis here in America. It was the first digital currency to come to market in the world. Bitcoin continues to be the most decentralized [owned by the people of the world - Peer to Peer (P2P)], secure, private, auditable, cannot be counterfeited, and finite (limited to 21 million to be made for total supply) on the planet. Click the “Gift Bitcoin” at the top of the page to privately gift Bitcoin for a 30% discount at DR. DUSTIN PLATTNER or click here.
Here is one of the best sources for an almost complete review on how to use and understand bitcoin: Bitcoiner.Guide
A good bitcoin wallet for your computer is Sparrow Wallet.
A good bitcoin wallet for Android and Apple is Zeus
To buy and sell bitcoin Peer to Peer (P2P), sovereignly, and anonymously use Bisq (however, it is has a steep learning curve).
To get more information regarding bitcoin read the Bitcoin Wiki.