Santa Claus (Saint Nicholas/Sinterklaas/Father Christmas/Kris Kringle) is a legendary figure who brings presents to children if they are good.
The red coat with white collar and cuffs with red trousers became popular in the United States & Canada because of a significant caricaturist and political caroonist Thomas Nast. Because of films, television, songs and etc this image has been maintained.
Santa Claus lived in the far North Pole while Father Christmas lives in Finland. He is married with Ms. Claus and with the help of the reindeer he travels around the world distributing presents and joy.
Nicholas (from Bulgaria) was the first inspiration for Santa Claus. He was famous for distributing gifts to the poor.
I've heard people say before that Santa is physically like that because of the Coca-Cola commercials. But in my research I found nothing like it.
Merry Xmas to All!