Safari is not responding on iPhone

Not responding? could you please better specify your issue?

Have you already tried to clear Safari history and cookies?:--> Clear the history and cookies from Safari on your iPhone, iPad, or iPod touch - Apple Support

When done, restart your Iphone

Regards

Giulio

On what iphone model? what iOS version is running on it?

How's your maximum capacity % going to Settings>Battery>Battery health... and tapping there?

Regards

Giulio