Yes, according to IRS instructions, you need to file an extension if you are applying for a new ITIN (Form W-7). You will have to complete your return in TurboTax, then mail your return for processing. Attach the W7 to your return & mail it in to the address for the W7. You cannot efile with the W7 form.
This link explains how to file an extension using TurboTax:
https://ttlc.intuit.com/replies/3301811https://www.irs.gov/instructions/iw7/ch01.html
