What is equivalent of MQL5 OrderModify() function
in MQL5? I searched a lot and
could not find.
Thanks for any help.
In MQL5 you should use OrderSend function to make any trade operation.
Please read https://www.mql5.com/en/docs/trading/ordersend and https://www.mql5.com/en/docs/constants/structures/mqltraderequest. It might be helpful.
You also can use standard library functions. Please read here (https://www.mql5.com/en/docs/standardlibrary/tradeclasses/CTrade) for more information.