The core of blockchain technology is defined by its immutable nature. The term immutable is defined as something that cannot be modified or changed once created.
Immutability is the need of the blockchain network which comprises of several nodes that must agree on the validity of the data before letting it pass. Blockchain networks are used as distributed ledger technologies just to make sure that there is no individual entity that can modify any records present on the blockchain.
Immutability is the ability of the blockchain to record, store, and exchange data in such a way that once recorded, it cannot be modified without altering the subsequent blocks present in the network. It is the cryptographic hashing that makes the blockchain immutable. Immutability lets blockchain achieve security, and data integrity, and also prevents frauds.