If a song is currently playing on your HomePod, you can manually access playback controls in the Music app from your iPhone or iPad. Below are the steps how:
NOTE: This procedure also works with Apple TV audio on HomePod.
Manually Accessing Playback Controls for Your HomePod in the Music App
STEP 1: On your iPhone or iPad, launch the Music app.
STEP 2: Tap the Now Playing banner at the bottom of the screen – just above the section tabs.
STEP 3: Tap the Airplay icon at the bottom center of the screen.
STEP 4: Tap your HomePod Now Playing panel.
STEP 5: Tap the Play/Pause button to play or pause audio.
STEP 6: Tap or press the Skip Song to skip a track.
NOTE: Be reminded that you can’t skip back to a previous track.
STEP 7: Drag your finger across the playback slider bar to scrub forward or back on a track.
STEP 8: Drag your finder across audio slider bar to increase or decrease the volume.