How to get rid of black box on iPhone 15?

Hello~ Try this… Settings > Accessibility > Spoken Content > Speech Controller > Show Controller > Off.

~Katana-San~

Go into the Settings app and open the "Accessibility" menu. Tap "Spoken Content" in the Vision section, then toggle on the "Speak Screen" switch. That's all you have to do. If you want to use spoken content but want to hide the controls, you can turn off speech controller.