I would, to you and to others reading, not recommend adding an input field asking the user what trigger is used in the Zap - at least if you are planning on making your Zapier integration public. Unless there’s a clear, user-centered, reason for requiring it, and unless the user experience of providing the info is made super easy, the integration is likely to be rejected by the review team. I’d rather you not get that far and have to fundamentally rework things. (If you’re building this for your own use, of course, you’re free to build however you like.)
Further, and more importantly, your action should not need to depend on the specific details of the rest of the Zap, and that’s generally a signal that something needs to be rethought. We’re happy to help come up with alternative approaches if you can share why you need, and how you’ll use that information.