Hi there, @HeatherCarver.
Thank you for posting in the Community. Allow me to help share additional details about recording historical data in QuickBooks Online.
To start, I've provided short descriptions below about the transaction types you see in the drop-down list.
Check- You use regular checks to pay for a fixed asset, inventory and non-inventory part, service, other charges, and any expense you track.
Deposit- You can use this when recording your customer payments. You can either deposit each payment directly into a QuickBooks bank account, or you can group payments together to be moved to that account later.
Sales Receipt- Used for goods/services rendered at the time of a purchase (sometimes referred to as a "point of sale" purchase), or if your customers give you immediate payment.
Receive Payment- If you issue an invoice, you use Receive Payment to record customer payment.
Bill Payment- You use this when you make a payment to a bill which you owed to your vendors.
Refund- Issue a refund check when you need to return an amount to your customer.
Expense- Recording transactions directly paid by either bank or credit card.
Transfer- A transfer you've made between two balance sheet registers
Journal Entry- You can use it when the other transaction types do not apply.
Additionally, the following articles contain more information about recording historical transactions in QuickBooks:
These resources should help to get you back on track and enter data in QuickBooks. Stay in touch if you have any other questions about recording prior transactions in QuickBooks. I'll be happy to help you out. Have a great day ahead.