How do I file with a W-7?

TurboTax doesn't include Form W-7, so you'll have to download it directly from the IRS, fill it in, and print it out (see these IRS instructions for help with that).

Then, complete your return as you normally would.

If you are a US citizen and your spouse does not have a Social Security number or an ITIN and you are not applying for an ITIN with the tax return then you can only file your tax return as Married Filing Separately.  Where asked to enter the spouse's Social Security number enter 999-88-9999.  You can only print and mail your tax return, it cannot be e-filed.  When you print the tax return erase the Social Security number for your spouse and manually enter NRA for non-resident alien.

See this TurboTax support FAQ for the procedure to print and mail a tax return using the online editions - https://ttlc.intuit.com/questions/1944348-how-do-i-print-and-mail-my-return-in-turbotax-online

Bring your printed, signed return (along with any attachments per the filing instructions, such as W-2s or 1099s), the completed W-7, proof of identity, and foreign status documents to your acceptance agent or an IRS Taxpayer Assistance Center.

Alternatively, you can mail everything to:

Internal Revenue Service
Austin Service Center
ITIN Operation
P.O. Box 149342
Austin, TX 78714-9342

See also General ITIN Information at IRS.gov.