Battery % meter for the iPhone 13 Pro home screen

This is not possible, there is no room to display all of the current icons and the battery percentage. You can, however, add a battery widget to the Home Screen.. or swipe down on the right top side to see the battery percentage from the Lock Screen.

Home Screen widgets are wonderful and provide needed information at a glance. Please see this Apple tutorial that explains how to add widgets: Add widgets on iPhone - Apple Support

Start here:

Use widgets on your iPhone and iPod touch - Apple Support

You need to add the battery widget to your home screen.

Here’s how:

1. Tap and hold the Home Screen until the icons jiggle
2. Tap the plus + icon (upper-left corner of Home Screen)
3. Scroll down and tap the Batteries widget

Here’s a demonstration video:

You’re welcome! 😉