No email - Your backup identity

Hi there. I’m trying to sync iphone with mac and windows. But all of them require another device to confirm. And i don’t have email ‘Your backup identity’, probably removed it. And also I don’t have access to my old PC, where I first time initialized sync.

Is there a way to resend this email to me?

No there is not such option, there are plenty cases like yours described here on forum, please follow one of them.