In Add/Edit form go to settings -> Notification settings.
Change the submitted success message by changing “Email success notification”
Change the submitted error message by changing “Email failed notification”
Redirecting to Thank-you page after submissions:
- Change “Action after submit” to “Redirect to thank you page”
- Provide the “Redirect Url”
- Now, when the form is successfully submitted it will be redirected to the page URL you provided.