hi my apple phone does not responding it cannot be updated or restored in itones finally it says that the phone cannot be found . how can I fix it .

See if this document helps:

'If your computer doesn't recognize your iPhone, iPad, or iPod'

click here --> https://support.apple.com/HT204095

If you are using iTunes make sure it is the absolute newest. Check for updates:

Update to the latest version of iTunes - https://support.apple.com/HT201352

A few users of High Sierra have reported needing to delete iTunes and reinstalling iTunes in order to get the latest version.

An alternative is to update over wi-fi:

Here's a simple and fast way to see what is possible with your device, including updating it to the highest sub-version (e.g., 12.5.4 --> 12.5.5) of an iOS/iPadOS you may already have:

On your device, tap:

Settings > General > Software Update.

1. If it says your device is up to date there is nothing more you can do. If apps you are trying to use say you need a higher iOS version, you will need to buy a newer device if you want to run those apps or features.

2. If it says an update is available you will normally only be given one update selection which will be the highest available iOS version supported by your device. However, if you are running an iOS 14 version that is OS 14.5 or greater, you may see two options. Click on a link below for full instructions about how to update wirelessly, or using a computer (see links in document) if you have storage or connectivity issues. If the update listed is not equal to or higher than the iOS version you need to use a feature, you again will need to buy newer equipment if you want to use that feature.

Update your iPhone, iPad, or iPod touch. Click here --> https://support.apple.com/HT204204

Or this video:

"How to update your iPhone or iPad" click here --> https://youtu.be/csJAEyvvruY