Hi @LaibaMehnaz
DISCLAIMER: I haven’t tried this myself , and as Sam found in his experiments mBART doesn’t always give good results.
for mBart source seq ends with src lang id and tgt seq starts with the tgt seq id. so for summ you can pass the same lang id for both source and tgt lang and then finetune it the same way you finetune any other seq2seq model.
For translation, if the lang is not present, you can try without using any lang id in the sequences.