I received an invoice for $5.40 for AppleTV. I do not use AppleTV. Can you explain this charge to me.

• If you see 'apple.com/bill' on your billing statement - Apple Support. Investigate charges that you see. A bank/card statement doesn’t specify the product, just the merchant.
• See your purchase history for the App Store, iTunes Store, and more - Apple Support. The purchase history will specify exactly what each charge is for.
• See your subscriptions overview - Apple. If you have unwanted subscriptions, then you can cancel those.
• Request a refund for apps or content that you bought from Apple - Apple Support. If the transaction is eligible for a refund, then you can request that.

The Apple TV+ subscription is $4.99/mo plus applicable tax. The subscription does not start on its own. Someone, either you, a family member, or a friend started the subscription. Or perhaps you took advantage of the free trial and forgot to cancel. Either way you can cancel the subscription by following the instructions in the link below.

How to cancel a subscription from Apple