Hi,
Firstly, you need to update iOS. You are running outdated software; the latest is iOS 16, specifically iOS 16.0.2.
It sounds like you subscribed to Apple Music, and if so, you would need to complete the following:
- Enable Cellular Data
- Settings > Music > Sync Library should be enabled
- Automatic Downloads should be enabled
- Download over Cellular should be enabled
If you have concerns about cellular data usage, you can limit which apps are allowed to use cellular data in Settings > Cellular > Apps Using Cellular. I would not recommend completely disabling it. Just disable the preferred apps. To keep up with your cellular data usage on a monthly basis, you can Reset Statistics in Settings > Cellular on the same day each month.
Apple Music uses a feature called Sync Library.
This allows content to be downloaded to your device two different ways:
- Downloaded to Library
- Downloaded to Library for offline streaming
When you download content to your Library, but it has not been downloaded for offline streaming, you will see the content in your library, but it will have a cloud icon with a downwards arrow beside it. To download content for offline streaming that has been downloaded to your library, tap the cloud icon.
The difference between the two is that content downloaded for offline streaming can be accessed no matter what. This applies to cellular data being disabled, cellular service being inactive, network connectivity issues, no service, no SIM, etc. Content downloaded to your library, but not downloaded for offline streaming, requires a stable wifi or cellular connection to stream the content, because it has only been added to your library, not downloaded.