For merchants utilizing Clover Go, there is an Android ePayment app available for free at:
https://play.google.com/store/apps/details?id=com.simplepos.epaymentmobile
For the ePayment app to allow you to send invoices, you do need to subscribe to at least the $19.99 plan. The selection of the subscription plan must still be done through the Clover App Market. The pay per invoice option is not available on the Android app platform.