How to know if you have a spyware on your iPhone?

Greetings Wensical003!,

We see that you have some concerns related to malware or malicious software on your iPhone. We're happy to assist.

Apple uses a number of methods to ensure that the software you install to your iPhone from the App Store are safe. Our site App security overview contains additional information on the measures used to keep your device secure. Keeping your device up-to-date is recommended to ensure you have the protection of the latest security enhancements which you can learn more about at Apple security updates.

We hope this helps!

Fortunately for Apple fans, iPhone viruses are extremely rare, but not unheard of. While generally secure, one of the ways iPhones may become vulnerable to viruses is when they are 'jailbroken'. ... Apple takes issue with jailbreaking and seeks to patch vulnerabilities in iPhones that allow it to happen.

So, are you on iOS 14.6? If so, then that drains a lot of battery. It’s possible that your friend could have updated it your phone. And if it’s that case, he didn’t do anything wrong. Updating your phone almost always makes it healthier, often adding new features, more performance, better battery life, and bug fixes. But the iOS 14.6 update has brought battery drain to a lot of people.

then you asked what jail braking is, this should tell you everything.https://www.techradar.com/how-to/phone-and-communications/mobile-phones/what-is-jailbreaking-1322927

(please note: this link is not spyware.)