How do you change the battery display to percentage

On an iPhone with Face ID: Swipe down from the top-right corner. On an iPhone with a Home button: Go to Settings > Battery, then turn on Battery Percentage.

Show the iPhone battery percentage - Apple Support (IN)

There is no room in the status bar on a phone model with Face ID for battery percentage. You can view it on the Control Center as SravanKrA posted, or you can add a battery widget to the Home screen:

Here are instructions for adding widgets to the Home screen→https://support.apple.com/kb/index?q=iphone+widgets&src=globalnav_support&type=organic&page=search&locale=en_US

im not sure how to do that with the battery.. can u tell me how to do that?