I want to have an insurance for my iPhone

In the USA and UK at least, you can buy “AppleCare+ with loss and theft” which has Apple partnering with an insurance company (Asurion in the USA) for the loss and theft coverage. It, like regular AppleCare+ must be purchased within 60 days of buying your device from Apple or an Apple Authorized seller.

AppleCare+ for iPhone XS, iPhone XS Max, iPhone 8, and more - Official Apple Support

Or you can just get insurance from any mobile device insurance company where you are.

Apple does not sell insurance. It sells extended warranties. How to buy an AppleCare plan for your device - Apple Support and Where to buy AppleCare+ for your iPad, iPhone, iPod touch, and Apple Watch.

You can buy AppleCare+ from Apple pithing 60 days of iPhone purchase.