As you travel from Kingdom to Kingdom with Mario, you will actually be able to purchase and obtain different outfits for everyone's favorite hero. Most of these costumes can be purchased from the Crazy Cap Stores found throughout the game; however, there are still some that can be unlocked by scanning a certain Amiibo (all Amiibo Outfits can be unlocked as well by obtaining Power Moons) or by obtaining a certain amount of Power Moons. In total, there are 40 Outfits you can obtain to customize Mario.
Crazy Cap Stores (Purple Coins) Outfits
Top Hat & Tuxedo, Caveman, Sombrero & Poncho, Cowby, Swim Wear, Explorer, Scientists, Aviator, Astronaut, Builder, Golfer, Snow Suit, Resort Wear, Chef, Painter, Samurai, Happi, Nintendo 64 Outfit
Crazy Cap Stores (Yellow Coins) Outfits
Employee Uniform, Boxer Shorts, Fashionable Outfit, Mechanic, Black Suit, Pirate, Clown, Football Player, Skeleton
Amiibo Outfits
Classic, Luigi, Dr. Mario, Waluigi, Diddy Kong, Wario, Bowser Wedding Tuxedo, Peach's Bridal Dress, Gold Mario
Unlockable Outfits
Mario Cap & Suit, Captain's Hat, Wedding Tuxedo, King, Hakama, Metal Mario, Invisibility Hat