How do i complete update on my iPhone connected to my pc?

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

If you connect your device to your computer with a USB cable and iTunes doesn't recognize your iPhone, iPad, or iPod, get help.

When iTunes on your computer doesn't recognize your connected device, you might see an unknown error or a "0xE" error. If you do, follow these steps and try to connect your device again after each step:

1. Make sure that your iOS device is unlocked and on the Home screen.
2. Make sure that you have the latest version of iTunes that works with your computer.
3. Check that you have the latest software on your Mac or Windows PC.
4. Make sure that your device is turned on.
5. If you see a Trust this Computer alert, unlock your device and tap Trust.
6. Unplug all USB accessories from your computer except for your device. Try each USB port to see if one works. Then try a different Apple USB cable.*
7. Restart your computer and iPhone, iPad, or iPod.
8. Try connecting your device to another computer. If you have the same issue on another computer, contact Apple Support.
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For more help, follow the steps below for your Mac or Windows PC.

* Learn how to connect iPad Pro (11-inch) or iPad Pro 12.9-inch (3rd generation) to your computer.

If you use a Mac

1. Connect your iOS device and make sure that it's unlocked and on the Home screen.
2. On your Mac, hold down the Option key, click the Apple menu, and choose System Information or System Report.
3. From the list on the left, select USB. 
4. If you see your iPhone, iPad, or iPod under USB Device Tree, get the latest macOS or install the latest updates. Then uninstall third-party security software. If you don't see your device or still need help, contact Apple Support.
5. 

If you use a Windows PC

The steps differ depending on if you downloaded iTunes from the Microsoft Store or from Apple.

If you downloaded iTunes from the Microsoft Store

Follow these steps to reinstall the Apple Mobile Device USB driver:

1. Disconnect your device from your computer.
2. Unlock your iOS device and go to the Home screen. Then reconnect your device. If iTunes opens, close it.
3. Click and hold (or right-click) the Start button, then choose Device Manager.
4. Locate and expand the Portable Devices section.
5. Look for your connected device (such as Apple iPhone), then right-click on the device name and choose Update driver.
6. 
7. 
   
8. Select "Search automatically for updated driver software."
9. After the software installs, go to Settings > Update & Security > Windows Update and verify that no other updates are available.
10. Open iTunes.

If iTunes doesn't recognize your iPhone, iPad, or iPod - Apple Support

https://support.apple.com/en-us/HT204095

See instructions here, Update your iPhone, iPad, or iPod touch - Apple Support. You should find the iPhone icon in the upper corner of the iTunes sidebar.

See if this helps https://support.apple.com/en-us/HT204095