The work of validating transactions and adding them to the Blockchain is performed by miners or validators. Miners use powerful computers to confirm the transactions as well as maintain Blockchain network. For doing this, they are rewarded with fees called as transaction fees for every transaction that is confirmed and included in the block.

These transactions fees are over and above the block reward they get for adding every block to the Blockchain network. Usually miners, prioritize validation of transactions that carry higher fees.