You can set a nicely-worded completion message to display when a user completes your form, or you can take them directly to the next step in your process or any other web page by setting a redirect.
A form redirect is a good tool to use if there's some extra information you'd like to provide to form users; whether that's to encourage them to take another action or provide more detailed follow-up information.
To set a completion redirect on one of your forms, navigate to the editor of the relevant form. Select the Completion page from the right side panel of the editor.
The completion options will appear on your screen. Select Redirect to external link, which will bring up a space for you to enter the URL you wish form users to be redirected to on form completion.
Once you publish this change, all form users going forward will be redirected to the link you've entered.