RNA stands for Ribonucleic acid, and it's the kind of nucleic acid involved in processes such as DNA transcription, and the translation from nucleotides into amino acids and eventually into proteins. mRNA or messenger RNA is the molecule involved in the process of replication, by the RNA polymerase intervention, which is an enzyme that helps to unzip DNA for mRNA to synthesize.
Molecules such as tRNA or transference RNA, help the process occurs in the ribosomes; these molecules (tRNA), are the ones that carry copies of each codon's (groups of three nucleotides) amino acid, while rRNA or ribosomal RNA is a subunit of the ribosomes where the genetic information is transformed into proteins.