See -> If your computer doesn't recognize your iPhone, iPad, or iPod
If your computer doesn't recognize your iPhone or iPad - Apple Support (CA)
Troubleshooting:
Turn your iPhone On and unlock it -> enter the passcode.
Go to Settings -> set Auto-Lock to Never.
Connect your device to your computer using an Apple USB cable & try also another USB cable.
Make sure your Windows PC is up to date.
Update to the latest version of iTunes : Update to the latest version of iTunes for Windows 10 – Apple Support (UK)
See also -> Check your third-party security software.
Check the Wi-Fi connection.
Turn Off Hotspot.
Turn Off or remove VPN if necessary.
Disable all AV & Firewalls temporarily while you connect your iPhone.