What is Form 2106?
Form 2106, Employee Business Expenses is used to report unreimbursed travel, meal, entertainment, and transportation expenses (including DOT per diem) you incurred while working as an employee. Form 2106-EZ is a simplified version of this form.
TurboTax automatically creates Form 2106 or 2106-EZ when you go through the Job-Related Expenses part of the interview. You can get there by searching for 2106 inside your TurboTax program and then clicking the Jump to 2106 link in the search results.
Tip: It's possible to accidentally create this form when it doesn't apply to your tax situation, for example if you enter info about your "daily driver" or a Schedule C business vehicle. This will throw errors during the Smart Check. Fortunately, an errant Form 2106 is very easy to remove from your return.