Read the WhatsApp Business Policy (eng) at this link.

Briefly:

• You can send messages to the client only if they have given you their number and you have obtained their explicit consent to send messages via WhatsApp.
• You can initiate communication from the business side only using templates approved by Facebook.
• You can respond to a message from the client without a template if less than 24 hours have passed since the last client message.
• Facebook monitors the quality of mailings, so clients should not complain to Facebook about you. If the complaint rate exceeds a certain threshold, Facebook may disable the account.

Read the WhatsApp Commerce Policy at this link.

It indicates which products and services are prohibited to sell through WhatsApp. Anything not indicated, and that is allowed by law, can be sold through WhatsApp.

Businesses in Cuba, Iran, North Korea, Syria, Crimea, Donetsk, and Luhansk cannot use the WhatsApp business platform. All other regions can.

Select a number for connection. You can use any mobile or landline number. The number must be confirmed by call or SMS.

Make sure there is no WhatsApp application on the number.

The WhatsApp application is not supported, work is only through CRM\helpdesk. If there is an application, it will be necessary to delete the WhatsApp account and the application, and the WhatsApp application on the phone cannot be restored.

Therefore, you cannot connect your personal WhatsApp number to the CRM\helpdesk that you use on your phone. You need a separate number without WhatsApp.

Проверьте, что у вас есть Бизнес-менеджер Фейсбука, что к нему есть доступ.  https://business.facebook.com/settings/info/   Найдите свой Business Manager ID (номер) и Business verification status (верифицирован или не верифицирован).

Make sure the company details are filled out in the Facebook Business Manager and that a working website is indicated. The company and website are mandatory for connection. The company details in the Facebook Business Manager must match the company details on the website.

Campaigns up to 250 clients per day do not require Facebook Business Manager verification, although we still recommend doing it.
To increase the campaign limit to 1000 clients per day, Facebook verification is required: manual.
The limit up to 10,000 clients per day is automatically increased if you run campaigns to 2000 clients in 7 days without user complaints.
The limit up to 100,000 clients per day is automatically increased if you run campaigns to 20,000 clients in 7 days without user complaints.