Waverunner for agencies is white-label performance advertising. Your agency is a parent organization. Each client is its own workspace: businesses, campaigns, ads, and reporting stay separate.
Clients see your name, colors, and logo. On day one we give you a Waverunner subdomain. When you are ready, point your own host at that subdomain with a CNAME. Exact records show in the agency console.
Clients do not sign up on your domain. You create the workspace and send a branded invite when you want them to log in.
More detail: Agencies documentation.