Should my transaction date be the date of when I sent out the invoice or the date I received payment for the invoice?
Recording your transactions accurately is essential for the integrity of your bookkeeping. For inquiries like this, it's always best to consult with your accountant to ensure you're receiving the best advice for you and your business. If you're not yet connected to an accountant, you can connect with one in your area through our website: Find a ProAdvisor.
In the meantime, I'd be happy to outline the most commonly used workflow when entering transactions in QuickBooks Online.
An invoice transaction is a two-step entry. First, you create and send your invoice. Second, you record the payment. The date the invoice was created will be the one you'll likely want to apply to the invoice. When you receive the payment, you'll enter the date the payment was received on that transaction.
I hope this helps, however as mentioned it's a good idea to consult your accountant.