You can't. You cannot file a tax return until you get your W-2's and employers have unti the end of January to issue W-2's. The IRS will not accept a tax return until the end of January.
If you are asking about a refund loan, the TurboTax refund loans have to be offered-- you cannot opt in, and you must have a completed, accepted tax return to receive the loan:
https://ttlc.intuit.com/community/refunds/help/about-refund-advance/00/27333#sh-collapse1
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**