Here are some tips and tricks for saving your iPhone's battery power:
Adjust screen brightness: Lower the screen brightness to conserve battery power. You can also enable Auto-Brightness to automatically adjust the screen brightness based on ambient light.
Turn off Wi-Fi and Bluetooth: If you're not using Wi-Fi or Bluetooth, turn them off to save battery power.
Disable Background App Refresh: Background App Refresh allows apps to refresh their content in the background, which can use up battery power. Turn it off for apps you don't use frequently.
Enable Low Power Mode: Enable Low Power Mode to reduce power consumption by turning off certain features, such as mail fetch, automatic downloads, and some visual effects.
Use Airplane Mode: Use Airplane Mode in areas with poor cellular coverage or when you're not using your phone to conserve battery power.
Close unused apps: Close apps that you're not using to conserve battery power. Swipe up from the bottom of the screen to access the App Switcher and swipe up on the app to close it.
Disable location services: Some apps use location services, which can use up battery power. Disable location services for apps that you don't need them for.
Use a dark wallpaper: Use a dark wallpaper, especially on iPhones with OLED displays, to conserve battery power.
Update to the latest iOS version: iOS updates often include battery optimization improvements, so make sure your iPhone is running the latest version.
Use optimized battery charging: Enable Optimized Battery Charging to reduce the wear on your iPhone's battery by limiting the amount of time it spends fully charged.