HOW DO I DELETE WIDGETS?
Hmm.. I don't think it's because they are pre-installed. If I were you, I'd install a 3rd party home launcher.
I got that but some are not deleted they just stay where they were? IDK what's up with that? Is that they are pre-installed apps?
Press and hold the widget and see if after a second or two an X icon or trash can icon shows up, drag it there.