Why is there a charge from Apple to my account yet there’s no purchase receipt sent to me?

I have been charged by Apple several times and I can not find out why. I do not have any recurring subscriptions. There was no receipt of purchase sent to me. When I check the site for a purchase history, there’s nothing listed. How can I get to the bottom of this? My bank account reflects a charge, yet there’s no record of it for me to access.