Hi @jess,

The best practice is to have one main mailing list that all of your opted in contacts route to. This way, when you are identifying contacts to send a campaign to, you can be certain that the contacts being pulled from the main mailing list are opted in to receive email marketing. In the signup form editor, you have the ability to adjust the list that a form routes to.

As for the welcome flow, you would set that up so that the flow triggers off of that main mailing list that both forms are routing subscribers to. You will then add a conditional split with the condition of “Properties about someone where $source equals > (insert $source value of the pop-up form). For every signup form in Klaviyo, there is a $source value attributed to the profile of every subscriber that equals the name of the sign-up form. 

Therefore, If the user came through signup form with the $source of the popup, they will go down the ‘Yes’ path. This is where you would insert the communication with the discount.

If they signed up through the form with the $source of the embed, then they will go down the ‘No’ path. This is where you would insert the communication with no discount.

I hope this helps!

Julie