Hello,
Log in to your WordPress admin dashboard.
Navigate to “Appearance” > “Themes.”
Look for the currently activated theme. In the theme details, you will see information about the theme.
Or in your WordPress installation directory, navigate to the “wp-content/themes/” folder.
Look for the theme folder that corresponds to your currently activated theme.
Inside that theme folder, check for the presence of a “style.css” file. If it contains a reference to a parent theme in its comments, it’s a child theme.
Best Regards.