TurboTax does not provide the statement. The statement that you have to send to the IRS is a copy of your 1099-B showing the details of the individual sales.
TurboTax will not tell you that you have to mail the statement until you go through the final filing section. That's because you don't have to mail anything separately unless you are e-filing your tax return. TurboTax doesn't know whether you are e-filing or filing by mail until you actually start the filing process. After you select e-filing, TurboTax will create Form 8453 and tell you that you have to mail the statement. If you file by mail, Form 8453 is not used. You just attach the statement to your mailed tax return.
