Shopify expert needed to customize email confirmations based on which product is ordered.

At the moment Shopify sends the same confirmation email to all customers, but I'd like to have these customized based on the product they've ordered. Ie. If they purchase a consult through Shopify I'd like the email confirmation to include a link to my calendar booking program (Acuity).

I don't want to add another paid 3rd party app to do this, hoping there's a way to manage within Shopify. I've read that you can use webhooks, but I'm not sure what that is.

Please only apply if you definitely know how to solve this. Thanks