How can I add the submit button to my form?

I want to put a submit button to my form which i'm designing on free jotform so that whenever people sign in,after clicking on submit button,it will take them to thank you page

When using the SINGLE QUESTION IN ONE PAGE Form Layout, you won't need to add a SUBMIT button. The form will automatically add it at the end of your form.

And you won't need to setup the THANK YOU PAGE either. It works that way by default - When someone submits your form, they will be redirected to a THANK YOU PAGE. If you wish to edit the THANK YOU PAGE though, it's right below the SUBMIT button.