both are ok

I think is 'write it correctly'.

Both "write in the paper" and "write on the paper" are correct phrases, but they have slightly different meanings. "Write in the paper" typically means to write within the boundaries of the paper, while "write on the paper" can imply writing on the surface of the paper.

Write to whom in particular?

I tried to write but it seems it's not possible to write here in Bengali.Plz contact me via msg and I'll write there.

You write something out in triplicate.