How to customize the title from comments form?

it depends on the theme, but in general Comments are generated by the template : comments.php , you found something like that (example) :

<?php 
     $dro_pizza_comment_count = get_comments_number();
    if ( '1' === $dro_pizza_comment_count ) {
        printf(
            /* translators: 1: title. */
            esc_html__( 'One thought on &ldquo;%1$s&rdquo;', 'dro-pizza' ),'<span>' . esc_html( get_the_title() ) . '</span>'
            );
        } else {
            printf( // WPCS: XSS OK.
                /* translators: 1: comment count number, 2: title. */
                esc_html( _nx( '%1$s thoughts on &ldquo;%2$s&rdquo;', '%1$s thoughts on &ldquo;%2$s&rdquo;', $dro_pizza_comment_count, 'comments title', 'dro-pizza' ) ),
                number_format_i18n( $dro_pizza_comment_count ),
                '<span>' . esc_html( get_the_title() ) . '</span>'
            );
        }
?>

So we can change the words : thought by whatever we want