why is charging of tRNA necessary during translation process?

Charging of trna refers to the process of attachement of amino acid to a t rna in the presence of aminoacyl trna synthetase(enzyme).
During translation,polymerisation of amino acid takes place as per the genetic code on m rna.This requires the transport of aminoacid from the cytoplasm to the site of protein translation(ribosome).This is done by trna(adapter molecule), hence prior to translation,trna is charged so that it can ensure proper translation by transporting aminoacid toward ribosome and its polymerisation based on genetic code of mrna.
Hope this helps:)