Tagging an order during order placement can help in downstream analysis where multiple positions need to tracked to make decisions.
I would recommend that the v2 Order APIs ( https://api.fyers.in/api/v2/orders and https://api.fyers.in/api/v2/orders-multi ) should allow an optional payload parameter tag which would accept alphanumeric string values.
This value should also be added to the response from Tradebook (https://api.fyers.in/api/v2/tradebook) and Orders api as well. and Positions ( https://api.fyers.in/api/v2/positions ) APIs