I want to get a receipt for the purchase of my iPhone

If you purchased it online you should be able to view your invoice and print it out via the Apple Store app or on the website

https://secure.store.apple.com/shop/order/list

If this was a purchase you made in store depending on how long ago it was you may be able to contact the store to see what your options are or check to see if you have an email with the invoice

This is a user to user forum. You are not addressing Apple here, we cannot send you a receipt here.

You will need to contact the store you bought the iPhone from to get a receipt, or if you bought it online, log in to your account to get a copy.

click here ➜ Viewing & Changing Orders - Print Invoice - Apple

Contact the store where you bought the phone.

This is a user-to-user forum, not a way to communicate with Apple. No one here knows anything about you, least of all a receipt.