There are a few ways to pause audio on Apple AirPods:

Double-tap one AirPod. This is the default way to pause audio on AirPods. To do this, simply double-tap the stem of one AirPod.
Say “Hey Siri” and then say “Pause.” You can also use Siri to pause audio on your AirPods. Just say “Hey Siri” and then say “Pause.”
Drag the volume slider in the Control Center. If you’re using an iPhone, iPad, or iPod touch, you can also pause audio by dragging the volume slider in the Control Center. To do this, swipe up from the bottom of the screen to open Control Center, then drag the volume slider to the bottom.
Remove one AirPod from your ear. If you’re only wearing one AirPod, it will automatically pause audio when you remove it from your ear.

Here are some additional things to note:

If you have Automatic Ear Detection turned on, your AirPods will automatically pause audio when you remove them from your ears. To turn on Automatic Ear Detection, go to Settings > Bluetooth > Your AirPods > Automatic Ear Detection.
If you have a Mac with macOS Monterey or later, you can also use your AirPods to control audio on your Mac. To do this, open the Control Center and click on the AirPods icon. You can then use the controls in the AirPod menu to pause audio, skip tracks, and adjust the volume.

Remember that AirPods are designed to work seamlessly with Apple devices, so the pause functionality is closely integrated with the playback controls on your connected device.