How can I get a duplicate bill for my iPhone?

If you bought it from Apple.com online you can log in to your Apple account and review your account details. It keeps your purchase receipts for 18 months.

If you bought it from a store you will have to ask the store. If you don’t remember the store and you purchased with a credit or debit card you can review your purchase history in the card’s website to find the seller.

If you purchased your device from Apple, you can request a receipt from the retail location.

Here’s how to locate the Apple Store and their contact information: Apple Store - Find a Store - Apple Apple Store - Find a Store - Apple

Check your email for a copy of the receipt.

If your purchase was made at the Apple Online Store, please view the section titled “View or Print Invoice” here: Viewing & Changing Orders - Shopping Help - Apple Viewing & Changing Orders - Shopping Help - Apple

If your device was purchased from an Apple Authorized Reseller, it is recommend contacting them directly for a receipt.

Keep your receipt after you buy an Apple device

Keep your receipt after you buy an Apple device - Apple Support

Apple does not have access to receipts generated by other merchants. If you purchased from Apple, what store? If you purchased from another merchant, you’ll need to ask them, when you remember who it was.

Well, if you can't remember where you bought the phone we certainly can't help.