Nov 06, 2017 - 03:10 AM
To add items from your computer to your iTunes library do either of the following:
Drag a file or folder from the desktop to the iTunes window.
If you add a folder, all the files it contains are added to your library.
In iTunes, choose File > Add to Library, locate a file or folder, and click Open.
Once you've added the files that you would like, you can then sync to your iPhone.
Here are the steps to do so: https://support.apple.com/en-us/HT201253