Hey there, auditors-acuvat-. I'm here to share more information about tracking transactions so you can record the sales and purchases in QuickBooks Online.
When you say "the same party" are you referring to a third-party application? Any details can help me provide accurate resolution.
QuickBooks has two options for recording sales depending on when you receive the payment. The same goes for the purchase.
You can use Sales Receipts if a customer makes an immediate payment. If it's a deferred payment, create an Invoice and record a payment against it when the customer pays.