A bankruptcy case number (sometimes referred to as a docket number) identifies a particular case. It’s assigned when the debtor files the initial paperwork with the court.
The case number allows you, your creditors, the court, or anyone else to access the electronic version of your court file on Pacer (bankruptcy documents are public records). Pacer is the online filing system used by the bankruptcy court.
The case number appears on all documents filed with the court. Not only will it be in the caption (the box at the top of the first page), but the clerk will stamp it in the top margin of the document, too. You can also find it on all notices mailed out by the court.