All in-game purchases are processed by the app store you used to download the game (Google Play/App Store/Huawei AppGallery/Amazon Appstore/Microsoft Store).
You can find more information about your purchase history in the customer support section on the Apple, Google, Huawei, Amazon, Microsoft websites.
Note: every time you make a purchase, a receipt is sent to the email address connected to your Google Play/Apple ID/Huawei/Amazon/Microsoft account.