iphone 8 iOS15.1 how to double tap on back to silence Alarm Clock ?

Hello there SunnyInToronto,

Thanks for posting here on the Apple Support Communities! This is a place where other Apple users can submit questions or respond to others to help lend a hand. Let's take a closer look as we do our best to provide some additional insight.

We understand you're trying to use Back Tap on your iPhone. For more help with that, be sure to take a look at the steps in this resource here: Use Back Tap on your iPhone This resource was found using Apple's Knowledge Base: Apple - Search for topics

We hope this helps get you pointed in the right direction.

Take care.