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/Samsung Galaxy Store).
You can find more information about your purchase history in the customer support section on the Apple, Google, Huawei, Amazon, Microsoft, Samsung Galaxy Store websites.
Microsoft Store
Samsung Galaxy Store
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/Samsung Galaxy account.