You never send paperwork to Turbotax.
In a few rare cases (about 8-10 specific situations) you will be required to mail certain documents to the IRS within 3 days of e-filing. If this is the case, Turbotax will tell you when you get ready to file.
In even rarer cases, your tax return might contain a form or situation that can't be e-filed and you will have to print, sign and mail your entire return to the IRS, your state, or both. Again, Turbotax will warn you.