To change copyright text, go to Customizer»Footer»Copyright Text
Also on footer, you have option to show / hide footer widget from Homepage, Single Post, or Archive.
By default, on footer, you have 3 widget. but you can also alter those widget to use only 2 widget instead of 3. Most of time, you will use only 2 widget if you are using no sidebar. if you choose to use only 2 (two) widget, you will only need to fill Footer Widget 1 & Footer Widget 2. But if you are using 3 Widget, you will also need to fill Footer Widget 3 with widget.