Hi Lourdes,
These blog posts will show you how to pre-fill Forms using URL parameters and JavaScript:
- http://blog.clickdimensions.com/2014/06/pre-fill-forms-from-links-or-webpages.html
- http://blog.clickdimensions.com/2015/05/pre-fill-forms-from-links-or-webpages-part-2-using-hidden-fields.html
Hopefully this helps!