QBI deduction for residential rental real estate

I have a Sch E for a rental home, with about $3000 in net income.  This income generated a $600+ QBI.  When I print out my return, the last page is titled, "Rental Real Estate Enterprise Statement."  It has a statement that says, "By signing this return, we affirm . . . . " a set of statements that are true in our case.  At the bottom is a "Under penalties of perjury, I declare that I have . . . and such facts are true, correct, and complete."  (which they are)

 

My question:  There are lines at the bottom of this form for signature(s) and date.  DOES THIS HAVE TO BE PHYSICALLY SIGNED?  OR IS SIGNING OUR E-FILED RETURN ADEQUATE?  If it has to be physically signed, does it have to be snail-mailed?  And if so, with or without our e-filed return?  

 

Thank you SO much for your help!