All, I’m trying to help a friend add several audio book chapters Apple Music on her iPhone, without using a computer. She has a Windows Surface computer that belongs to her employer, and doesn’t want to install Apple Music/iTunes (or anything personal) on the computer, so we’re trying to get the MP3s into Music without using a compute.
The MP3s are currently stored on a Synology Drive, which she’s accessing using the Synology Files app, and has downloaded the MP3s from Synology Files to Apple Files. However, neither of us can figure out how to get them into Apple Music. The MP3s can be played from Files, but they don’t save played the location, when you stop playing the audio, unlike Apple Music. Within Files, the MP3s can be moved/copied to iCloud, but I’m still not sure how to get them into Music.
Install the VLC app, which can play audio files from storage. It takes a bit of fiddling, but works fine.
I just tried it with some audio files that I have on my iCloud Drive and it seemed to remember playback position for me when I tried it.
You can’t put media files into the music app from the device itself. It requires either using iTunes (or the Music app on Catalina or later) or using Apple Music using one of those apps to sync or stream to the Music app on the device.
The only way to copy music to an iOS device in a way that can be played by the Music app is using Apple software. Either iTunes (on Windows and old versions of macOS) or Music (on modern versions of macOS).
BTW, you appear to be confusing “Music” (the player app) and “Apple Music” (the streaming service). It can be a little confusing because the Music app is the way you stream music from Apple Music, when playing it on a Mac or iOS device, but they are two different things.
As others have said, it’s not possible to add MP3s (or other audio files) to the iOS Music app without a computer. However, for your use case, you’re much better off using the app BookPlayer. Even though I sync my phone with Music on my computer, I switched to BookPlayer a while ago, as it’s far superior to Apple’s Books or Music apps for playing audiobooks (and better than VLC which is a general media player). It’s nothing fancy, but does one thing and does it well, including allowing you to create folders or a single book out of multiple files. It can import audio files from the Files app/iCloud.