He's not referring to giving you a receipt, he's talking about voting machines that produce a paper print out that the voter quickly confirms at the polling pla

He's not referring to giving you a receipt, he's talking about voting machines that produce a paper print out that the voter quickly confirms at the polling place, then deposits in a ballot box. If the custody these paper ballots is managed carefully, they can later be used to verify any apparent funny business in the results of the electronic vote counting system.