Question

Can I upload documents now in BGC form of TCS or should I do later ?

Answer 1

A bird in hand is better than 2 in a bush. Unless you have anything better, I would say go ahead and accept it.

Meanwhile, if you want to join product companies, keep preparing and applying on the side, don't wait for an year.

Answer 2

You can upload now but remember one thing that if you submit it now then you have to wait for it's approval or rejection ; only after that  u may upload new documents .