You need to have NFC on your phone. This is a wireless data transfer method that allows contactless payments via Google Pay.
We invite you to read this article on Google Pay Help for more details: Check if your phone can make contactless payments
Note: The use of MuchBetter cards and wearables is temporarily out of service. Unfortunately, MuchBetter cards or wearables cannot be activated in the app for now, nor used for purchases or ATMs. However, you can keep it with you safely and we will confirm when you are able to proceed with activation or its use.