Is it possible to set a specific URL as the landing page upon submission?

Also I would like to know if I can add an specific url as landing page when the user finish the form OR to redirect to the same form when the user finish it (to do the same form many times from the same device)

Yes. You can direct users to other pages or to the same form. Click on the THANK YOU PAGE under the SETTINGS tab. Choose "Redirect to external link" and add the URL of the same form or another page. The users will be directed to the URL you typed upon submitting the form.

You can also have a look at this user guide: https://www.jotform.com/help/38-Redirecting-Users-to-a-Different-Page 

I hope this helps! Please feel free to ask if you need further assistance.