You cannot sign up for the 2025 tax refund advance. It can only be offered to you after you have completed your 2025 tax return that includes a federal tax refund and are ready to e-file the return.
The TurboTax 2025 tax refund advance will not be available until after January 1, 2026
TurboTax support FAQ for the 2025 tax refund advance - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-refund/refund-advance/L52Mg0G5u_US_e...
