Two piece shirt collar

The two-piece shirt collar is constructed of two different collars: the bottom part - the band - which is basically the Mandarin Collar with an extension to the value of the button placket, and the top part is the Turnover Collar, but with a different shape to the collar points.

reference:

https://www.dresspatternmaking.com/garment-elements/collars/two-piece-shirt-collar