Need my iPhone 11 invoice bill

Have you check your mail box?

Or get help and assistant from Apple directly, see -> Contact Apple for support and service

Contact Apple for support and service – Apple Support (UK)

or

Call 1-800-MY-APPLE

As Apple require the bill to prove ownership they will not short circuit the process by providing such proof to anyone who requests it.

Login to https://privacy.apple.com/

Request all data on your AppleID. 

After a day or two, you’ll be able to download a fair number of CSVs containing YOUR data as held by Apple. 

tip by Chattanoogan