WhatsApp Business API - what platform or software to use

Hello folks,
Honestly, I am a bit lost here.
My boss asked me how can we improve, elevate our Whatsapp Business. We are doing fine, but raising the bar never hurt anyone.
So, I am at a loss dealing with the API .
I asked around, I was told that I need to contact Facebook directly and ask for an invitation key.
And later I need to choose a platform from where I can use the API to do out bidding.
Anyone can shed some light here?
Thanks in advance for your time and knowledge!

I don’t use WhatsApp. but I also don’t know what your goal is.

I can explain what we use out Whatsapp channel for.
We have a large list of people pre-ordering our products.
We already set up the automatic responses, catalog and business hours.
But we want to automatize it even more, to have a tracking order or the posibilty to send to our large list of clients promos, QR codes for discounts and so on…

Looks like I am starting to answer my own question.
After a bit of searching, the solution could be provided by some certified Fb certified partners who offer their API seamlessly integrated with WhatsApp.
Now, which one?
Twilio, Sinch, Tyntech…
Anyone has some insights on using WhatsApp API?