How to position the "Thank You" page?

I would like to have in the middle of the page or at bottom so when the client is finished with the form that will see it was submitted. How do I Achieve this?

I am not quite sure if I understood your concern correctly. But if you would like to edit your "Thank You" page, you can easily do that in your "Thank You" wizard.

Here's a guide that you can refer to: https://www.jotform.com/help/211-Setting-Up-the-Thank-You-Page. You can click the "Edit Text" button and from there format your "Thank You" message layout.

If I misunderstood your concern, please do provide us more details of what you would like to accomplish.