What a media notification is
A media notification is the playback card that appears in your shade when music, podcasts, or video are playing. It carries play, pause, skip, and seek controls plus the app name and artwork.
What you can control
Tap play or pause, skip forward or back, drag the progress bar, and on many phones adjust the output device (phone, Bluetooth, speaker) right from the card. Output switcher and thumbnail also live there.
Why it sometimes will not go away
Media notifications are usually persistent: the card stays while audio keeps playing in the background, even with no visible app. Clearing it stops playback. A "persistent" tag is normal for players.
How to remove it
Swipe the card away to stop the player and dismiss it. If an app leaves a stuck media card after playback ends, force-stop the app or clear its notifications from Settings → Notifications → App notifications.
A note worth keeping
A media card controls sound; it does not keep your other reminders visible. For an alert you must not lose — an address, a code — Dingpin pins it to the top of the shade alongside the player.