How do I capture a speaking audience without turning it into a pitch?

I keep speaking to corporate audiences and getting warm reactions — people line up, ask for my Instagram, say they want to work with me. Then it stops. My membership for leaders in Brazil is the offer I most want to grow, but I don’t know what I should be trying to capture in the room: the follow, the email, or the sale. I’ve tried one QR code to a free resource. Fourteen sign-ups, one became a member, and my team didn’t follow up the others for nine days. I don’t want to turn a keynote into an infomercial. What are you actually capturing when you speak, and how do you do it cleanly?