https://www.youtube.com/watch?v=ashe_4phX_Y

Does anyone know the name of this style of dressing, where you have a shirt with a collar that comes out of the sweater? I really like that look and was wondering what to look for. Does anybody have any suggestions on how to start building one or two of those outfits?

The picture is unrelated to the question, tank you in advance for any answers.