Gather materials: 1 Nether Wart, 1 Golden Carrot, Water Bottle
Brew an Awkward Potion: Water Bottle + Nether Wart (in a Brewing Stand)
Brew a Potion of Invisibility: Awkward Potion + Golden Carrot (in a Brewing Stand)
(If using splash/lingering) Add gunpowder to the Invisibility potion to make a Splash Potion of Invisibility
(If using lingering) Add Redstone Dust to the Invisibility potion to make a Lingering Potion of Invisibility
Drink the Potion of Invisibility or throw the splash/lingering version to apply invisibility