Int this configuration activity you are able to crate document type which will be used later when posting in cash journal.
IMG Path: Financial Accounting (New) -> Bank Accounting (Business Transactions) -> Cash Journal -> Define Document Types for Cash Journal Documents
Tables: T003, T003T
In the first screen you will see the list of all transactions.
On the screenshot below you will see how the standard document type for vendor invoice is defined. Maintain based on your requirements.