Directly Through Facebook
For businesses to create a WhatsApp business profile, it comes with a tad bit of approvals. To enable the WhatsApp Business API for your business, submit your industry profile for consideration using this link:
To start with this, you need to sign up directly. Going with this process is somewhat technically challenging for small businesses.
For example, to set up WhatsApp business API, you need a developer even though you can get the entire process details on the Facebook official support pages.