If you are looking for your Tax ID number or Employer Identification Number (EIN) in your personal return that you filed online with TurboTax Free, Deluxe, Premier or Self Employed, you should be able to find it on your printed paperwork on form Schedule C (if you had independent contractor income or a business). It is located on the upper right hand side of the screen (see screenshot below).
If you need to print a copy of last years return, see link below that explains how to do so:
https://ttlc.intuit.com/replies/3301525
