GTT is a limit order which stays active until the trigger price is met. Pocketful gives 1 year validity for a GTT order after which it'll be automatically cancelled. Once the stock hits the trigger price, an email on registered mail and a notification will be sent on the app.
Note: On Pocketful, GTT can only be used for Cash and Carry (CNC) orders in the equity cash segment on NSE and BSE.