You can change what happens when you double tap your AirPods, from summoning Siri to pausing or skipping tracks

Open Settings and then click on Bluetooth

Connect your AirPods to your iPhone by opening the case

Leave the case slightly open to ensure they stay connected, and press the i icon on the right hand side

Select either the left or right AirPod and pick what you'd like a double tap to do

You don't have to have the same action on both - you can choose different things for left and right