QIF import is available only for asset and liability accounts (including house and vehicle) and cash accounts. If you have purchased Quicken Home & Business, you can use QIF to import transactions into accounts payable accounts and invoice accounts as well. QIF import is also available for any exported list, but the file you want to import the list into must already include a valid account.
QIF import is not available for checking, credit card, savings, 401(k), or any other brokerage accounts. To import transactions into these types of accounts, see the improved download solution replacing QIF.