Unfortunately your question is confusing because you used terms for your iPhone and your account issues that have nothing to do with each other. Invoices for purchasing an iPhone have nothing to do with accounts.
So, if your issue is your account has been disabled for “security reasons” the solution is to reset your password as outlined in this document: If you forgot your Apple Account password - Apple Support
If you find you can’t sign in, reset your password, or receive verification codes, you can request account recovery (read this support article: How to use account recovery when you can’t reset your Apple Account password - Apple Support ) to regain access to your account. More detail in —> Activation Lockout Issues - Apple Community For additional assistance from Apple Security, read: Contact Apple Support - Apple Support
You only need an invoice if you are asking Apple to reset the entire iPhone. Note that if this is locked because a previous owner did not remove the lock, Apple won't reset it for you unless the person who sold hte iPhone to you also provided you with the original receipt for sale from Apple.
Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. Check the requirements and steps at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not detail what currently constitutes proof other than it “must include the product serial number, IMEI or MEID.” Apple may typically require the original receipt* issued by Apple or an Apple Authorized Reseller. If Apple resets the device this will give you access to the device but won't restore access to the account used to lock it. There is nothing that can be done to expedite an Activation Lock request.
*Apple recommends you "Keep your receipt after you buy an Apple device" --> Keep your receipt after you buy an Apple device - Apple Support
