Hi @tandt, welcome to the community!
I love that idea with the QR code that leads people to a secret page with a capture form. I’ve done this for my own events, and it works great!
So the short answer is, yes - of course! You can create a page in Shopify (e.g. /pages/event) and then on that page, simply embed a Klaviyo Signup Form that captures any information you’d like to subscriber to provide.
Just note, even in an embedded form, you can still use “multi step forms” too - so you can have the first step capture the basic information (like email) and subsequent steps collect additional information if they choose to provide it. It might seem a little less daunting and you might get more people to at least submit their email address if they are not ready or willing to provide you their mobile number.
You can learn more about that here:
As a bonus tip, at my events, if you complete this Form it goes to a unique Klaviyo List that then triggers an automated “welcome flow” specific to the event so they get an “auto response” once they signed in.
I also configure the “source” attribute of each of the Signup Forms (for each event) so I know which event they submitted to since I reuse this page at each of the events that I host by simply changing the source value each time. That way, I can simply create a Segment of all folks that signed up from a specific event since they will have different “source” values.
Hope this helps!