How can I remove pop up box appeared on my iPhone screen?

Go to Settings - Accessibility- Spoken Content>Speak Screen and turn it off.

If Speak Screen is on then swiping down from the top of the screen with two fingers will activate this feature. It speaks whatever is on the screen.

It sounds like you've accidentally triggered VoiceOver, which is an accessibility feature that reads aloud the content on your screen. To turn it off, follow these steps:

1. Go to Settings on your iPhone.
2. Tap Accessibility.
3. Under the Vision section, tap VoiceOver.
4. Toggle VoiceOver off.

Alternatively, you can also turn it off quickly by triple-clicking the Side Button (or the Home Button if your iPhone has one) if that feature is enabled in your accessibility settings. If it’s not VoiceOver causing it, it could be the Speak Screen feature. You can find that under Settings > Accessibility > Spoken Content, and make sure Speak Screen is turned off.

You have turned on the screen reader. See this article: Hear iPhone speak the screen, selected text, and typing feedback - Apple Support

You can also say, "Siri, turn off VoiceOver."

anniau wrote:

Thanks I tried that. Voice Over is turned off.

https://discussions.apple.com/content/attachment/c3b43e19-e1a7-4c4a-9fd5-c4973e038f76

The annoying box is still there.

That's because it's not from Voice Over. The instructions I gave were for how to turn off Screen Reader. Please read them again, carefully.