Do I need to declare or fill any form for the money I transferred from US to overseas (say India, China etc). While filling tax? The amount transferred is between 80-100K in 1 year.

You do not need to declare the transfer.
*If it is a gift, you may have to file gift tax return.
*If you are transferring to your own account, you will have to file Form TD F 90-22.1 and/or 8938 Specified foreign financial assets (SFFA).