Take goods to other state by self and sell goods there

MY CLIENT DOING BUISNESS OF TRADING OF GOLD ORNAMENTS. HE IS REGISTERED UNDER GST IN GUJARAT. IF HE CARRY GOODS WITH HIM TO OTHER SATE SAY ODISA AND SELL GOODS THERE, WHAT DOCUMENTS HE NEED TO CARRY WITH HIM, DURNING TRASNIT ??? AND WILL HE NEED TO TAKE REGISTRATION IN THAT STATE ALSO?