There is nothing to mail unless you were told to do so when you e-filed your tax return.
See this - https://ttlc.intuit.com/community/print-and-file/help/do-i-need-to-mail-anything-after-i-ve-e-filed/01/26144
Unless you have been specifically told to submit a form on paper you don't need to mail anything if you have filed electronically.