Hash function is defined as a computer program that takes information and turns it into a series of letters and numbers of a certain length, this process is non-reversible.
For example, “I like bitcoin” can be hashed and will equal: ad3e58f21b94f32dcadca6b71df4c31a18179f38011551a17a80d0ff065d22c5
If I were to capitalize the “b” in bitcoin, so it says, “I like Bitcoin” the hash will be completely different: d988ca30eaa88c0410ad6e48a5297c0d505dcee572f9884f1a6fa2cbc8dedc86
Hashing is used to make storing and finding information quicker because hashes are usually shorter and easier to find. Hashes also make information unreadable and so the original data becomes a secret.