To answear that question, you need to undrstand blockchain, you need to undertand distributed ledger tecnology. blockchain is like the name sugest. the main server node, running on servers in computer. any one can run a btc core, that interact with other btc core.network is called blochain. the whole network of nodes updates all time on each other. data is growing. like potatoes. every block of btc is updated to core. who run son your pc. you add your own coin blocks to your own core with adress. you may even get money for fee on trancfer other btc tranceactions from whole diferent places.