There is a great demand for oversize coats on the market when compared to oversized coats for women. So you have to search for oversizes here. In the end, you buy it online. Retailers focus mainly on the narrow-cut or narrow-cut dresses, some focus mainly on the large sizes.
So there are retail stores in your country that sell big coats. But if you look at the number of stores, there are only a few. So it is not possible for people to travel through the distant shops to buy a perfect oversize coat.
The last thing left is the internet. Here you can choose from a variety of oversized coats so you can buy the one that suits you best. This also has one drawback: you can not taste the clothes you can do when you go to the retail stores.