The subscription purchase is maintained by Google Play Store and the invoice is also provided by Google Store.
When you buy a device or accessory on the Google Store, you won’t be charged for your order until it’s shipped, usually a few days after you ordered. How to obtain a receipt is well described in the article Your Google Store charges and receipts
Get a VAT invoice
If you live in the European Union, Switzerland, or Norway, learn how to request a VAT invoice.