If you're looking to change your emoji skin color permanently, there are a few things you can do. First, make sure that you have the most recent version of iOS installed on your device. Next, go to Settings > General > Accessibility > Display Accommodations > Color Filters. From here, you can select the Color Tint option and choose the color you want your emojis to be. Once you've made your selection, tap Done and then toggle on the Color Filters switch at the top of the page. Your changes will now be permanent!