The transaction is made from your wallet to the network. The network miners validate your transaction and record it in the blockchain. To send Bitcoin you need two things: A Bitcoin address (public key) and a private key. The Bitcoin addresses are generated randomly and of course mathematically.
They are in form of simple series of letters and numbers and you can share them with others. The private key is also in form of series of letters and numbers and is fully related to public key. The private key is the heart of your wallet, you miss it you lose your money (Bitcoin) and never be shared with others. Private keys can be used for wallet recovery also.
Everyone has access to your private key can own your asset or your money. So keep it secure and private.