There may be times when you need more customization flexibility than the theme options (customizer) allows. Now we are entering into a different world of customization that involves Child Themes.
IMPORTANT – Never edit theme or plugin files!
The problem when editing a theme file is that whenever there is an update, you will lose everything you did. This is because an update will overwrite the theme files with the new files.
This is why WordPress strongly recommends you make theme changes with a child theme. To learn more on how to make a child theme, you can visit their guidebook on getting started.