TurboTax will fill out Form 8453 automatically if there is something in your tax return that requires you to mail to the IRS one of the forms listed on Form 8453.
What is it that you need to mail to the IRS with Form 8453?
Are you using TurboTax Online or the CD/Download TurboTax software?
Are you a paid tax preparer? You cannot use TurboTax to prepare returns for clients. TurboTax is only for do-it-yourself consumer use and cannot be used by paid preparers. Intuit (the company that makes TurboTax) has three tax software product lines for professional preparers: ProSeries, Lacerte, and ProConnect. You can find information about all three product lines at the following link.