How to obtain a bill for my iPhone?

If it was from Apple Store you would have received the invoice on your email, provided by you to them while making the purchase.

With online Order Status you can Print an Invoice

Log into Apple

1. Click on the bag icon as shown in the above
2. Click on Sign in
3. Click on Orders
4. Click on the items that you want an invoice for.
5. Click on View Invoice under the Order Number Top right-hand corner. See the pic below...

There you have it.

I want new bill because I forgot my bill

How to obtain a bill for my iPhone iPhone XR 64gb black colour

Contact the store where you got your phone for a copy of the receipt.