Note: if you have the Google Drive App installed on your phone you can simply click on the three dots to the right of the file and select “make offline”. That’s it!The Files app brings all of your files together in iOS 11. You can easily browse, search, and organize all your files in one place. Not just the ones on the device you’re using, but also those in apps, on your other iOS devices, in iCloud Drive, and across other cloud services.
To download an MP3 to iPhone/iPad so you can listen to it offline please follow these 5 easy steps.
Check that your device is using iOS 11 or later and if not update your iPhone, iPad, or iPod touch to iOS 11 or later.
Touch the download link
When the player starts to play the MP3 click in the top right corner where you see the three vertical dots and select “Open in”>
Wait while the MP3 downloads (it will say “preparing to export”) and when it finishes touch “Save to Files” and select which folder you want to save it “On my iPhone” (you can also save to iCloud Drive or other installed 3rd party apps) touch “Add”
When you go to the Files App on your home screen you will find the MP3 file, touch it and it will play without needing any internet or 4G connection!