Local File Discovery is a new way that the Spotify app can help you find your music files that aren't hosted by Spotify. It’s as simple as accessing a playlist in Your Library.
To access your local files on iOS devices, follow these steps below (Desktop and Android app users head here.):
1 – Open the Spotify app on iOS.
2 – Click on Settings 
3 - Scroll down to the Local Files option and select it.
4 – Switch Show audio files from this device on.
Note: A pop-up will ask permission to access your local network. Accept this permission to enable Local Files transfer between desktop and mobile.
5 – Now, go back to Your Library 
6 – Follow the steps below to transfer your audio files according to your device:
6.1 – macOS:
- Connect your iPhone to the Mac with a cable.
- Open Finder on the Mac, find the Locations section in the sidebar and select your phone.
- Drag and drop the tracks.
Note: Make sure the option “Manually manage music, movies, and TV shows” is turned on. You can access this option in your device sync settings within Finder, under the General section.
6.2 – Windows:
- Install iTunes and connect iPhone to the computer.
- Open iTunes, then select your phone from the pop-up in the sidebar and click Music.
- Drag and drop the tracks.
Note: Make sure the option “Manually manage music, movies, and TV shows” is turned on. You can access this option on iTunes in your device sync settings, under the Options section.
7 – Go back to Your Library 
Local File Discovery is available worldwide on Android and iOS, for Premium and Free users.
