A valid phone number is mandatory for all WhatsApp Business API accounts. Please go through the points given below before choosing a WhatsApp Business API number. 

• Your business needs a valid phone number and short codes are not allowed on WhatsApp. 
  ‍
• The number can be a Landline or mobile phone number. However, you must own this number since it is going to be tied to your WhatsApp account.

• The number must include a country and area code. 
  ‍
• This phone number must be able to receive voice calls or SMS in order to complete registration.  
  ‍
• If you wish to use a phone number that is already active on WhatsApp, you will have to delete the existing account. You can refer to the instructions on how to delete an account here.
  ‍
• This phone number must not have been used with the WhatsApp Business API before. 
  ‍

Note: Once a phone number is registered on the WhatsApp Business API, it cannot be used for WhatsApp Business or the WhatsApp consumer app. A phone number can be upgraded to the WhatsApp Business API, but not downgraded.

‍