Hi @AJ_20,

Thanks for sharing this question with us.

1. There are several different ways to add a user to a list. I recommend reviewing our documentation on the topic here. Adding anyone to this list through one of the methods discussed in the documentation would immediately put them through the welcome flow (unless they have previously completed the flow). For users that were a part of the list prior to you setting it live, you’ll want to back-populate the flow to push those users through. Have a look at the thread below for a more detailed explanation on how to accomplish that:

2. There isn’t a way to automatically add a user to another list after completing a flow. However, you can add an update profile property action at the end of the welcome series. That will essentially “tag” the user with a property i.e. completed welcome series = yes. From there, you can create a segment based on that same property (properties about someone > completed welcome series = yes). This will automatically add users who completed the welcome flow to the segment because segments are dynamic (meaning they will automatically include users when the user satisfies the segment definition).

I hope that’s helpful.