The pay with refund option is only available if you have a federal tax refund and the refund is large enough to pay the TurboTax account fees. The option will be available only when the tax return is completed, all the required forms and schedules for your tax return have been approved and are available sometime after January 1, 2020.
See this TurboTax support FAQ - https://ttlc.intuit.com/community/payments/help/can-i-pay-with-my-refund/01/25711
