How do I change the text on the confirmation page?

After a form is filled out you can configure what is presented to the visitor who filled out the form. 

Step 1: Open the form in the form editor

For exported forms (Assets->Web Forms (External) ... find your form, click the pencil).

For forms in landing pages, open the landing page editor, hover over the form, click the pencil that appears on the form block)

Step 2: Click on the 'confirmation' tab

You have three options. 

1. redirecting the visitor to some other page on your site
2. build a custom thank you message (AD Constructs a page)
3. replace the form with an in place message

Redirect to another page: Place the URL in the text box, the page will redirect on submit:

Display the following thank you message: This option will create a very basic landing page. You do not have a lot of control over the format, but the page is quick to build.

Display the following message in place:  This option replaces the form with the message in the editor. Note, in place confirmations are not available if you are uploading files in the form.