With Photographic Styles iOS 15 (well, on iPhone 13 models), you can personalize the look of your images in the Camera app.
You can choose a preset — Rich Contrast, Vibrant, Warm, or Cool. You can also, if you wish, fine-tune it even further by adjusting the Tone and Warmth settings. Set your style once to use your preferred style setting every time you take a photo in Photo mode.
Set a Photographic Style
When you open the Camera app for the first time, tap Set Up to choose your Photographic Style. Swipe through the different styles and tap Use [Style Name] on the preset that you like.
Make sure to set your style before you start taking photos — you can’t add your Photographic Style to a photo after you’ve already taken it.
Change your Photographic Style
Want to change the Photographic Style that you set? Just open the Camera app, tap the up arrow, and tap Photographic Styles. Standard is the default, balanced style that’s true to life and can’t be customized, but you can swipe left to view other preset styles that are customizable. Tap Customize (the icon looks like a three pane window) to adjust the Tone and Warmth of the style that you’ve chosen.
(This how-to is based on my experiences and info on Apple’s support pages.)