TurboTax Desktop software: I entered summary data for form 1099B, at the end, the software asks me to print out form 8453 (checkbox form 8949). In previous years, I did so, and went to USPS and mail form 1099B. But after I e-filed, IRS processed and issued refund before I mailed out the document, or before IRS received the document, it seems that the document is not important for IRS to process tax return. As long as IRS thinks schedule D is correct.
In the future, I may go with freetaxusa, which allows attaching PDF files when e-filing, while TurboTax desktop software does not allow to do so, it is annoying to print out document and go to USPS.