You can see the info in the following TurboTax FAQ that explains the TurboTax Audit Guarantee. Note that this is different from "Audit Defense", which is a separate add-on service (costs extra) that includes personal representation.
"What is the TurboTax Audit Guarantee?"
https://ttlc.intuit.com/replies/3302288
*** I am NOT a tax expert. I am a seasoned TurboTax user, and volunteer to provide assistance to TT users. Nothing I post is to be considered TAX ADVICE; I bear no legal liability for responses.***