What Indian agencies mean when they search for this
Usually the agency is already running messaging for clients and the operating model has started to hurt. Numbers are scattered across vendor accounts, some of them registered under the agency itself, templates live in a spreadsheet, campaign results are reported as message counts because nothing else exists, and one client has just asked what happens to their data if they leave. The search is for a way to run six or ten client programmes with separation, evidence and a clean exit.
The ownership question you should settle first
Every other decision follows from who owns the WhatsApp business account and the number. If it is the agency, you gain a retention hook and inherit responsibility for consent collected by someone else, plus a difficult conversation at every exit. If it is the client, with your agency granted operating access, you lose the hook and gain something more valuable: the ability to say honestly that the asset is theirs, which shortens procurement and removes the argument that ends most agency relationships badly.
