How to capture user's location.

and the other is when they send the form I need to know from where I send it, with which geolocation field I should use it to be hidden.

The only widget which could be hidden, and still capture user's location is the Get Visitor Location: https://www.jotform.com/widgets/get-visitor-location

You may add it to your form to try it: https://www.jotform.com/help/252-How-to-Add-a-Widget-to-Your-Form

Let us know if you need more help.