can I change the link to a form to simplify it?

Customizing the end of the URL is quite easy:

http://www.jotform.com/help/261-How-to-create-a-Custom-URL-of-a-form

Using a custom domain is also possible, however, it requires your own server and familiarity with DNS:

https://www.jotform.com/help/144-How-to-use-Custom-Domains-with-Jotform