All are the processing reaction in tRNA, except:
Post-transcriptional modification of tRNA precursor:

Standard bases (A, U, G, C) undergo methylation, reduction, deamination, rearranged glycosidic bond.
Cleavage and attachment of CCA terminal at 3’ end takes place in cytoplasm.
Methylation of tRNA takes place in nucleus.

Note:- Poly A tailing is a processing step of mRNA primary transcript.
Reference- Harper 30th edition
CCA tailing
Methylation of bases
Poly A tailing
Trimming of 5’ end