Apple Music is a music subscription service similar to the ones offered by Spotify or Google, but much more deeply ingrained in your iPhone. There are several different options for the type of Apple Music subscription you can have, but all will charge you a monthly fee to use the service.
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How to Delete a Song from the iPhone Music App
While your iPhone has many options for streaming music and video directly to the device without downloading anything, you may decide to download some songs if you are going on a road trip and want to minimize the amount of data that you use. But those downloaded songs take up storage space on the iPhone, so you may need to delete them at some point to make room for new music or apps.