You will find the Kochi Dye Shop in Hateno Village (in East Necluda), and to proceed, you will need twenty Rupees and five items. These items can be a variety, including food, plants, and Monster parts. Bear in mind that some items cannot be dyed, but the shopkeeper Sayge will inform you if this is the case. Your whole outfit will be dyed in the color of your choice, so make sure you remove anything that you do not want to be the shade of choice. There are 15 different options here, provided you have the items to accommodate. With some patience and a little armor swapping, you'll look stylish in no time.