Attaching forms to 2020 South Carolina nonresident tax return

Generally, TurboTax does not allow attachments. It one is allowed, the program will give a prompt for a pdf.

If TurboTax efiling does not allow attachments, why does the software state to do so? The instructions should clarify that, and give an alternative for submitting the form. Postal mail is likely the only alternative.  But where do we send, and should a printout of all the pages be included?

This form is not part of your tax return because this form and payment are due by the 15th day of the month following the month of the sale.

The address to send this to is at the top of the form. https://dor.sc.gov/forms-site/Forms/I290.pdf

Thanks.