i was billed for something without my permission. Quizlet $38.15

To view your Purchase history:

1. Open the Settings app.
2. Tap your name, then tap Media & Purchases. 
3. Tap View Account. You might be asked to sign in.
4. Tap Purchase History.

Make sure no one else has access to the Apple ID that is listed under the Media & Purchases setting in step 2. I would also suggest resetting your password. Review this article about a compromised Apple ID:

If you think your Apple ID has been compromised - Apple Support

1.

If you have received an invoice from Apple, on every invoice from the Apple Store and/or iTunes Store always states what you have purchased (and/or concerns a subscription) and the amount.

Tap on Report a problem on the invoice.

Or try to ->  Request a refund for apps or content that you bought from Apple.

Request a refund for apps or content you've bought from Apple – Apple Support (UK)

If you have requested a refund, you must wait until Apple has approved. Then you will receive a message from Apple.

Refunds are not guaranteed. For more information, see the Terms & Conditions.

2.

Check for sure the following Apple articles:

View your purchase history for the App Store, iTunes Store, and other Apple media services

View your purchase history for the App Store, iTunes Store, and other Apple media services - Apple Support

How apps, content, and subscriptions from Apple are billed

How apps, content, and subscriptions from Apple are billed - Apple Support

If you see "apple.com/bill" on your billing statement

If you see "apple.com/bill" on your billing statement – Apple Support (UK)

3.

If the invoice has to do with an app that has a subscription associated with it, see -> Delete apps on your iPhone, iPad, and iPod touch -> Delete apps on your iPhone, iPad, and iPod touch - Apple Support

• If you delete an app, it doesn’t cancel in-app subscriptions that you might have. While deleting an app, you might see a Cancel Subscriptions option. Learn how to cancel your subscriptions.

If you don't want to continue a subscription you need always to cancel that subscription in time, see the following Apple articles:

If you want to cancel a subscription from Apple

If you want to cancel a subscription from Apple - Apple Support

If the subscription that you want to cancel is not listed

If the subscription that you want to cancel is not listed – Apple Support (UK)

4.

If the invoice is not from Apple, was the money deducted by a stranger?

Contact your bank, they can find out who (name, address & account number) has collected the amount from your bank account, and when.

Depending on your bank, they can collect the amount back within 30 days.

See also ⤵️

Identify legitimate emails from the App Store or iTunes Store

Identify legitimate emails from the App Store or iTunes Store - Apple Support

Recognize and avoid phishing messages, phony support calls, and other scams

Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support