Hi @user9509793 ,
Our Knowledge Base team does have a Tutorial Video for creating sign-up landing pages, which covers editing the form's thank you page where these elements can be added.
Since this thread is a bit older, and contains info from before the modern Automation Path Builder and Sign Up Landing Pages were released, I'll also provide links to relevant support articles for them:
Create a Sign-up Landing Page to collect new email and SMS contacts online
Getting started with the Automation Path Builder
Understanding triggers in the Automation Path Builder
... View more