GoKawiilIt all starts in the Settings app on your iPhone. Open it and look for the Battery menu — it's the one with the green icon. It should be easy to find since it's one of the first options in the list, near Wi-Fi and Cellular. Here, you'll find a detailed chart showing exactly how you've been using your iPhone. Tapping View All Battery Usage brings up an even more detailed list of exactly what's draining your battery. Even if you don't have one of the latest handsets, you can still access this information. It's been available since iOS 8.
The list is quite easy to understand. The apps at the top are the ones that drained your iPhone's battery the most. In most cases, these are the apps you use most throughout the day. Spent your afternoon watching TikToks? There's a good chance you'll see that app at the top of the list.
There's another key insight to look at. While On Screen refers to the time you actively used that app, there's also Background time. That's when an app isn't directly on the screen but is still utilizing your phone's resources.
Think of apps like Weather or Google Maps. When you let apps track your activity, they can check your location in the background even when you might not be interacting with them. The same goes for Apple Music or Spotify when they're streaming music with the iPhone screen off.