Hi @Brooke_Mac,
Thanks for sharing this question with us.
Using Klaviyo’s default signup forms, there’s no way to automate adding a “form submit date” to the profile as a custom property. With that said, when a user fills out a Klaviyo form (and confirms their subscription, if you’re using double opt-in for your lists), they will log a “subscribed to list” event on their profile. You can use this metric in segmentation too. For more information on this metric and it’s use-cases, see our article here.
I hope that’s helpful.
Has this been added to the development roadmap? Pretty basic feature