Where do I bulk change FROM email addresses login emails etc

I am changing our domain name for our business and want to change all emails associated with our IS account to be using the new domain, including the DKIM records. We are moving from girldirector.tv to girldirector.com

I’m having difficulty knowing where to go to change all of this. There doesn’t seem to be a default, baseline email for the system and I was hoping that I wouldn’t have to go into every campaign to change every email in there… Please help.