Open Spotify and play a song, album, or playlist
Tap the Shuffle icon so it turns off
If you are on mobile, tap the Now Playing bar, then tap the Shuffle button
If you are on desktop, click the Shuffle button in the playback controls
If Shuffle is still on, restart the app and try again
Make sure you are not using a playlist that forces shuffle on some devices or plans
Update Spotify if the shuffle button is not responding