Little dot on top

See this Apple support article—>About the orange and green indicators in your iPhone status bar - Apple Support

No, as stated above, it is a security measure to inform you when the microphone and/or camera are being used. As making or receiving a phone call requires a microphone, the orange dot will always show when on a call.

The orange dot simply indicates that the microphone is being used.

There is also a green dot showing when the camera is used.

It is a new security measure introduced with iOS 14.