For businesses that don’t sell a physical product, income is usually from services rendered. A service is an intangible product, and income derived from selling your services must be recorded in the accounting ledger. A journal entry in an accounting journal is a business transaction. A double-entry journal entry takes the form of a ledger with two columns; a debit column, and a credit column. It’s called double-entry because every entry into one column requires a corresponding entry into the other column.