When you make a purchase on Google Play, a confirmation email with your order information is sent to the Google Account you used to make the purchase.

You can also find your order information on Google Wallet by following these steps.

If you have additional questions on how to locate your order number, please use this link: https://support.google.com/googleplay/answer/2506346?hl=en

If you need to contact us for a purchase issue, please attach a screenshot of your receipt and make sure that the time and date of purchase is visible.

If you experience issues with this, or if you need to contact Support for a purchase issue, please submit a support ticket, by tapping the "gear" icon on the map screen, and then "support," or you can open an online support ticket here.

If you need help taking a screenshot from your device, here is a link with instructions on how to do this - https://support.google.com/android/answer/9075928?hl=en