A blockchain can be understood as a decentralized, distributed and public digital database or ledger where data gets registered once and never gets erased, which differs from typical databases in the way the data is structured.
A blockchain collects information in groups, known as blocks, with specific storage capacities. When the block is filled, it gets closed and linked to the previous one, forming a chain of data known as the blockchain.
The goal of a blockchain is to allow digital information to be recorded and distributed, but not edited. In this way, decentralized blockchains are the foundation of immutable ledgers, meaning that the transactions are permanently recorded - they cannot be altered, deleted, or destroyed - and viewable to anyone.
For this reason, blockchain is publicly recognized as a secure, transparent and resilient technology in several fields of application, as in order to change any data in any of the blocks it is necessary to have the consensus of the majority.