In order to create and register a WhatsApp channel with CM.com, you will need to provide a "Business Manager ID". This the number of your Facebook Business Manager account.
How do I know if I already have a FB Business Manager account ?
If your company already manages advertisements, events or an official Facebook page or Instagram account, then possibly you already have a FB Business Manager account. Make sure to check with different departments within your company, before making a new one.
Where do I find my ID ?
When you log into FB Business Manager, choose "Business Settings" and then "Business Info". Your ID should be listed just below your name.
How do I create a new FB Business account ?
Simply go to Facebook Business Manager and choose "Create account". Make sure to use the proper business details. If at any point you want to be blessed as the official account of a brand or tradename, you need to make sure you register the company that is officially owning that name.