Simply put, Immutability is the state of an object of not being given the capability of being changed or modified. In the field of Computer Science, Immutable Objects pertain to objects that cannot be altered after being created.
Immutability is one of the key features of the cryptocurrency, Bitcoin and its blockchain technology. When transactions are labelled immutable, these make it impossible for any entity, like a government institution or corporation, to manipulate, replacer, or falsify data that is stored within a network.
What immutability does is enable a high degree of data integrity. And with public transactions within a blockchain, the immutability enhances the current trust and auditing system.