Hi
Music and Now Playing apps
Under watchOS 4.x, for controlling playback of music from your iPhone rather than the synced playlists on Apple Watch (for which Bluetooth headphones or a Bluetooth speaker are required), then - other than by using Siri - it is necessary to first start playback on your iPhone before being able to control playback on your Apple Watch.
When you are already playing supported audio on your iPhone (whether via the Music app or a third-party app), the Now Playing app is shown automatically in the Dock on your Apple Watch and can be used to control playback on your iPhone. However, unlike under prior versions of watchOS, those controls no longer include the ability to browse or select playlists via screen-based inputs.
Now Playing can be configured to be shown automatically on Apple Watch upon raising your wrist when playing supported media on your iPhone. This is the default setting. To turn this feature off or on:
On your iPhone, in the Watch app, go to: My Watch (tab) > General > Wake Screen > turn off Auto-Launch Audio Apps.
If desired, Now Playing (as opposed to the Music app) can be added to the Dock permanently and/or added to a watch face as a complication. Note that not all size / positions for complications support the Now Playing complication.
Follow the instructions here:
Workout app
Having started playback of music on either your iPhone or your Apple Watch, if you then start a workout using the Workout app, in order to access the playback controls from within the Workout app, you can swipe from right to left across the watch face.
The Workout app can also be configured to automatically start playing a specified synced playlist from your Apple Watch upon starting a workout. This requires Bluetooth headphones or a Bluetooth speaker that has been paired to your Apple Watch. Playback from the selected playlist will only begin automatically if you have not already started playback of other music beforehand.
To select a workout playlist:
On your iPhone, in the Watch app, go to: My Watch (tab) > Workout > Workout Playlist.
To sync a playlist to your Apple Watch and connect headphones:
Overall features
If the Music and/or Now Playing apps do not offer all of the features that you would prefer, then you can submit a feature request to Apple here:
Feedback - Apple Watch - Apple
