Which of the following is considered a source document detailing the specifics of a sale or purchase?

An invoice is considered a source document because it provides a detailed account of a sale or purchase transaction. It typically includes essential information such as the date of the transaction, the parties involved, a description of the goods or services provided, quantities, prices, and total costs. This documentation serves as a formal request for payment and records the transaction for both the seller and buyer, thereby ensuring transparency and accountability in financial dealings.

Other documents, like a receipt, also provide similar information but are typically issued after the payment has been made, confirming the transaction rather than initiating it. A ledger, on the other hand, is a record used to summarize all transactions over a period of time and may include various entries from multiple invoices and receipts, rather than serving as a source document for a specific transaction. A journal entry serves as a recording mechanism for accounting purposes but does not contain the detailed transactional information found in an invoice. Thus, an invoice is vital for recording sales and purchases, making it the correct choice.