These are the default accounts we'll use for your non-order income and expense transactions.
The Amazon Bank Account is the account we'll use for your Amazon settlements. If you've recently created the account, then click on refresh for it to show up on the dropdown menu..
Some common income transactions are FBA reimbursements, while common expense transactions are inbound transportation charges and subscription fees.
By default, your current reserve balance is deposited into the default expense account and the previous reserve balance is deposited into your default income account.
You may want to create a bank account named "Amazon Current Reserve" in QuickBooks Online to map those two reserve balances so you'll always know what funds will be released on the next settlement period.