How share price of Indian companies are calculated in freetrade ? When I looked at price of HDFC Bank it was around 3 time higher compare to what we can buy in Indian stock market?

They are not shares per se but are American Depository Receipts (ADR).

The ADRs are created by a bank or broker that buys shares of stock in the country where they trade.
The bank then creates a derivative that is based on their purchased home country shares.