Iphone 11 Invoice

Hello, this is Alberto. I acquired an Iphone 11 more than 18 months ago in the US and now I´m back in Spain. I need the invoice of the purchase and I cannot find a way of getting it. I don´t have the confirmation email, I went to an Apple Store here in my city but is impossible to get it since is a different country. I tried to look it up in the website but I don´t have the order number either. It is very important for me to find it. I would be so grateful if you can find it.

Hope to hear from you soon.