It was very helpful. Thanks!An invoice is a bill. It is a request for payment.
A bill is something you receive in a restaurant or something sent from a company or an office to an individual person.
An invoice is usually a bill which one company sends to another company. It is a bit more formal.
A bill can have a somewhat negative connotation. Example: I got a bill from from my doctor's office and it was HUGE!
A receipt is a document stating you have paid the bill or invoice.