If you want to get the category with the link use:

If you want to get the category without the link use:

$categories = get_the_category();
 
if ( ! empty( $categories ) ) {
    echo esc_html( $categories[0]->name );   
}

It shows only the main category and not sub-categories. Echoing out only get_the_category will return array. Links: Code reference - get_the_categroy().