@lurengame,

1. You can use the "Voting / Liking Buttons" option. More info here:   https://wpdiscuz.com/docs/wpdiscuz-7/plugin-settings/comment-thread-features/#voting-liking-buttons

2. Or below is provided an example you can use: 

add_filter("wpdiscuz_comment_list_args", function ($args) {
    $args["voting_icons"] = ["<svg xmlns='    https://www.w3.org/2000/svg    ' width='24' height='24' viewBox='0 0 24 24'><path d='M12 4.435c-1.989-5.399-12-4.597-12 3.568 0 4.068 3.06 9.481 12 14.997 8.94-5.516 12-10.929 12-14.997 0-8.118-10-8.999-12-3.568z'/></svg>", ""];
    return $args;
});

This hook code should be put in the WordPress active theme functions.php file (more information on how to add and insert custom code):

Note: the code above is just an example. If you're not familiar with coding we don't recommend you change anything.