iPhone doesn't show battery percentage after iOS 16 update.

With my browser I can't see what phone you have. It is not available on mini models or phones older than iPhone 12

If you have a qualifying phone turn it on in Settings, Battery.

Shinchan69 wrote:

https://discussions.apple.com/content/attachment/6a1ecdb9-28ba-41e9-bf65-2407b9d9c009

Not all phones will be compatible with all of ios 16 features Show the battery percentage on your iPhone or iPad - Apple Support

You're out of luck then, sorry