If you want travel to abroad each country has particular regulation and when you want travel to Iran definitely there are some rules regarding to dress code which should take to consideration and you need to follow.
Women Dress Code:
The Islamic Republic of Iran requires women to wear loose fitting below the knee length garments and a head scarf. Legs and arms must be covered. The main one for the women tourist is the headscarf. The hairs have to worn at all times. It is necessary your neck cover as well as your head. In fact, bandana is unacceptable. Yet, If a little of your hair showing, it doesn’t matter and don’t need to be right up to your forehead unless in a shrine or a mosque.
How should cover Legs and Body?
Based on the dress code in Iran, you have to hide body shape likes Legs and arms. Thus, it is possible wear trousers either jeans or cotton. It is better legs covered down to the ankle. Besides, the shoulders should cover.