What do you need electronically signed if you are paper filing the returns?

We have some clients that are out of state that would like to file with us. I wanted to see if we can use the esignature functionality to have them digitally sign where they are at,  before we mail out the paper returns. 

I have to ask, why are you doing paper returns? 

IRS has a huge mail backlog from 2019 tax returns, and the postal "service" sucks.

IRS will not accept digital, scanned, or photographed signature on a paper filed 1040.

@sjrcpa 

I have to ask, why do you think they care?  (It could be a zero-balance return. And if there is tax owed, IRS gladly accepts online payments withut a signature.)

I have no idea.