Google Pay is a payment system from the US company Google for Android devices.
You can easily pay for your MOIA ride with Google Pay. You can select Google Pay from the MOIA app's menu under Payments. If you already have a form of payment in your Google Account, Google automatically syncs all compatible apps on your device. MOIA will automatically show you the "Google Pay" option in the episode.
You have never paid with Google Pay, but would like to do so? No problem, just deposit a form of payment in your Google Account.
Please note that MOIA does not accept American Express payments. Not even if this is deposited with Google Pay.
You can find more information about Google Pay here.