What are RNA used for?

Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and DNA are nucleic acids, and, along with lipids, proteins and carbohydrates, constitute the four major macromolecules essential for all known forms of life.

To aid in protein synthesis and allow it to occur.

Explanation:

There are many different types of RNA such as mRNA which transports the code read of DNA in the form of mRNA to tRNA to be make into amino acids and then proteins. rRNA is in the ribosome, which allows a part of protein synthesis to happen. snRNA edit mRNA and siRNA control protein synthesis.