Hello,
A decree finally decided rights and obligations between two parties (unless it is a preliminary decree). A decree normally follows a judgment.
Whereas an order does not finally decided the rights and obligations of two parties. Any formal expression of court which is not a decree is an order. In practical terms, a decree is formally and separately drawn by the court while the order sheet of the court consists of all the orders which are passed during the course of proceedings.
Apart from above, there are numerous differences between the two from an academic point of view. If you may please tell me as to why are you asking for the differentiation, I may be able to assist you more on this.
Thanks & Regards,
Nishant