Attempting to transfer files from your iPhone to a Windows PC, the true problem comes. Even after connecting with a USB cable, a few files occasionally fail to appear on PC. Here are 8 best solution. 

UNLOCK IPHONE BEFORE CONNECTING IT TO THE PC

Also use USB CABLE WITH SUPPORT FOR DATA TRANSFER

BEST WAY TO USE ITUNES TO TRANSFER FILES

ENABLE THE ‘KEEP ORIGINALS’ TOGGLE IN SETTINGS

USE A WIRELESS METHOD TO TRANSFER FILES

make sure you are using the original Apple USB cable

try to reinstall or update the Apple Mobile Device USB driver