Use WhatsApp API to send quote

So at the moment we’re using a normal mobile phone number for WhatsApp, and not clear on the API etc etc what it does and if we should be using it?

Key questions
1) If we use the WhatsApp API (business?) can we display Easy Step Flooring or will it always show a number.
2) Can we with or without the API capture the custom names + mobile numbers + chat transcript and push it to a CRM via API or something
3) What’s the advantages of using the API?
4) I have a discount i can utilise for 360Diaglog which is $5 per month. Would there service help in anything?

We don’t have a CRM at the moment so either we’ll build a bespoke on or ‘possibly’ use Freshdesk
What we need to do is

1) Get customer name + Mobile
2) Link to a custom and store their customer status and history (Asked for quote, asked for samples, ordered)
3) See transaction history