Your AirPods connect automatically to whatever device you're listening to (you must be signed in with the same Apple ID). For example, if you're listening to music on your iPad, you can simply start playing music, a podcast, or other audio on your iPhone to switch devices.
Are AirPods supposed to connect automatically?
If you're signed in to iCloud, your AirPods are set up automatically with any of your supported devices that are signed in to iCloud with the same Apple ID.
How do I get my AirPods to automatically connect?
Open your AirPods case and place it next to your phone. An on-screen animation will appear on your iPhone. Hold the button on the back of your AirPods. Click “connect” then “done.” Your AirPods are ready to use with your phone.