You can add your lead capture form to your Facebook Messenger Auto-Reply, by going to your Business page settings in Facebook:
- Click on Messaging, and scroll to "Response Assistant"
- Turn on "Send instant replies to anyone who messages your page"
- Edit the "reminder message" to say something like "Please fill out our contact form below so we can work on generating a quote for you!" Then add the link to the Lead Capture Form from 17hats (use the "View Form" URL)