how do i connect my iphone ro itunes

Connect iPhone to Computer / Mac

Settings > Touch/Face ID & Passcode > USB Accessories > [Enable]

You haven't mentioned whether you have a PC or Mac

Use your USB lightening cable --> Resolve USB-related alerts in iTunes - Apple Support

If unable to connect --> If iTunes doesn't recognize your iPhone, iPad, or iPod - Apple Support

For your Mac --> If your computer doesn't recognize your iPhone, iPad, or iPod ...

For your Windows PC —> Troubleshooting issues with iTunes for Windows - Apple Community

Use genuine cable --> Identify counterfeit or uncertified Lightning connector accessories ...

See how to --> Sync your iPhone, iPad, or iPod using iTunes on your computer ...

If you are experiencing an issue not listed here, contact support