Assuming you would like to offer Google Pay as a payment option on your WooCommerce store, you would need to choose a plugin that offers this option. One such plugin is the "Stripe for WooCommerce" plugin, which can be found here:
https://wordpress.org/plugins/woocommerce-gateway-stripe/
Once you have installed and activated the plugin, you will need to connect your Stripe account to WooCommerce. You can do this by going to WooCommerce > Settings > Payments, and then selecting "Stripe" from the list of available payment methods. After that, you will need to enter your Stripe Secret Key and Publishable Key, which can be found in your Stripe Dashboard.
Once you have entered your Stripe keys, you will need to select "Google Pay" as a payment option under the "ADDITIONAL OPTIONS" section. After that, you can save your changes and Google Pay should now be available as a payment option on your WooCommerce store!