Activation locked
I am uploaded my phone bill and after
Apple support mail is not additional information please tell me about additional bill information which one ?
iPhone 7
It sounds like you were using this service: https://al-support.apple.com/#/additional-support Apple does not provide a viewable list of what it requires for supporting documentation so you will have to contact them and ask (if they provide a method for doing that). I suspect what they want to see if the Apple Store receipt for the purchase of the device for which you are requesting a lock removal.
Apple recommends you "Keep your receipt after you buy an Apple device" --> https://support.apple.com/HT202711