This is the way to eliminate redundant data like :

Reduces null value

Enables efficient indexing

1NF – Removes duplicated attributes, Attribute data should be atomic, and attribute should be the same kind.

2NF – Should be in 1NF and each non-key is fully dependent on the primary key.

3NF – Should be in 2NF and all the non-key attributes which are not dependent on the primary key should be removed. All the attributes which are dependent on the other non-key attributes should also be removed. Normalization is done in OLTP.