How to cancel a pending payment on the App Store

See this support article about how apps, content, and subscriptions from Apple are billed and go to the section about pending charges for small amounts - How apps, content, and subscriptions from Apple are billed - Apple Support

If it is for something you purchased you will have to let the purchase proceed and then request a refund. Here's how to request an app or media refund from Apple (From: Request a refund for apps or content that you bought from Apple - Apple Support - see the article for more detail.)

1. Sign in to https://reportaproblem.apple.com

2. Tap or click "I'd like to," then choose "Request a refund."

3. Choose the reason why you want a refund, then choose Next.

4. Choose the app, subscription, or other item, then choose Submit.

If you were charged for a subscription that you no longer want, you can also cancel the subscription using the directions in this article --> If you want to cancel a subscription from Apple - Apple Support

You will have to cancel the subscription first, if this is reoccurring payment.

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

You could also request a refund, if you did not want to make this purchase:

Request a refund for apps or content that you bought from Apple - Apple Support