Put your domain and logo on every portal, email, and document, and give each client a separate tenant with the data separated in the database. Each client logs in to a portal on your domain, with your branding.
Brand the app and every surface, provision an account for each client, and let each client sign in and see only their own data.
Your logo, colors, and domain apply to the app, the tracking pages, the client portals, and the emails and documents that go out.
Create the client's account under yours. Row-level security in the database keeps that client's data, carrier accounts, and configuration separate from every other client's.
Each client signs in to the app on your domain with your branding, and sees only that client's orders, shipments, and invoices. Their customers get a branded tracking page.
We'll show the app and a client's sub-account under your brand. Or talk to us about a partner agreement.