Based on the dress code in Iran for tourists, you are supposed to hide the shape of your body. You should wear long skirts or trousers like jeans and cotton pants in line with the seasons.
You can wear skinny jeans or any other tight pants as long as they cover your calves, but since Capris are too short, they must be avoided.
Your top should be moderately loose and fall to nearly mid-thigh. Another option is a summer dress over jeans and a t-shirt. Bare forearms are fine in Iran but you should cover your shoulders.
Manteau
Manteaus are a type of tunic that usually reaches down to mid-thigh. Most women in Iran, prefer to wear a manteau which can be long, short, tight, or loose, and in different colors.
You can get yourself a trendy manteau for about 15-30 $ and use it as a light overcoat that covers your clothing.