Hi @HarlieJ Welcome to the Community!
There are lot of free app in the shopify app store for the same, you can use Shopify Inbox app for live support.
If you want to have the whatsapp icon and what customer to land on whatsapp then you can use other free apps.
For integration you just need to find the desire app and click on install button and then later on in the app you need to add your email and number.
Hopefully it will help you. If yes then Please don’t forget hit Like and Mark it as solution!
Best Regards
Sahil