Mining is the process used by Proof-of-Work blockchains to add new blocks to the blockchain and secure the network.
Miners use specialized hardware to repeatedly calculate hashes while trying to find a valid solution for a new block. A value called the nonce is changed again and again, producing a different hash each time, until the result meets the difficulty set by the network.
When a miner finds a valid solution, it broadcasts the block to the network. Other nodes verify that the block and its transactions are valid. If everything is correct, the block is accepted and added to the blockchain.
The successful miner receives a block reward, which is newly created cryptocurrency included in the block, along with the transaction fees from the transactions included in it.
Mining also helps secure the blockchain. Finding a valid block requires a large amount of computational work, making it expensive to create fraudulent blocks or attempt to rewrite the blockchain's history.
In this way, mining serves two main purposes: adding new blocks to the blockchain and helping protect the network from attacks.