if a number is already bound to a regular WhatsApp account you have to delete the regular account, then it can be used for Business.
The simple answer is yes, you can send documents, Video, Location (Early Access), and many more, but there is a limitation on the file size. to know more visit our link
Unfortunately, It's paid service from WhatsApp regarding the normal WhatsApp
application.
The API is associated with costs such as hosting fees, support, and conversation
fees as specified by Meta and WhatsApp. It is worth noting that the first 1000
conversations per month are free and after that, the conversation fees are
applied based on Meta’s rate cards.
META doesn't sell the service directly to the customers, The WhatsApp Business API is only available through Verified Service Providers.
portal.taqnyat.com is the right place to access your WhatsApp information, start campaigns, as well as you can export your campaign report, and see your sent messages