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 as you complete the FILE tab and the funds are only released to you after the IRS accepts your e-filed return.
TurboTax does not offer any type of refund advance on a 2022 tax return after 02/15/2023.
For tax year 2023, any type of refund advance from TurboTax will not be offered until sometime in January 2024.
Are you asking about your 2023 refund for next year?
It's too early to get an Advance. We don't know if they will offer Advances next year. If they do, you can't apply for it. Only if they offer it to you when you file.
When you go though the FILE tab right before you file, but....
The Advance doesn't come until after the IRS ACCEPTS your return. Usually the IRS won't start accepting returns until late January. Until then the returns just wait on Turbo Tax servers for the IRS to open. So filing early won't make a difference.
See these 2 links
https://turbotax.intuit.com/refund-advance
https://ttlc.intuit.com/community/refunds/help/about-refund-advance/00/27333