The refund advance loans are only given during tax season in January to mid-February. You cannot "opt in." The loan has to be offered to you, and is only given to you after the IRS accepts your e-file.
If you weren't offered the Refund Advance see,
Advance Details and Disclosures
https://ttlc.intuit.com/community/refunds/help/important-offer-details-and-disclosures-about-refund-...
