Hello,

I want to edit the report page but I can not find the template, you could tell me what is the name?

That page doesn't really have a template on it's own. The closest you'll come is probably core -> global -> forms -> popupTemplate. But that one is used for a lot.

What would you like to change exactly?

Remember that for the most part that report form should be loaded with ajax/as a popup form. People will usually not come to the page where it's displayed like that.