Add a field into a shortcode of an extension

I’m very nooby to WordPress dev so I’ll try to explain all the details I want, don’t know if it is possible!

I’m using an extension called wp-crowfunding, in it, you can add a project from the backend or from a shortcode. In my case, I’m using et shortcode. So in it, I have a lot of fields like “title”, “description” etc… but I want to add more fields.

My issue is that I can’t override the original template (called: /shortcode/submit-form.php) by copying the file in my theme (not working). So I asked myself if I could use my function.php to modify this file without destroying the extension. If this is possible, I don’t know how to do that.

To be more precise I need to add a WYSIWYG field in that shortcode.
If you need more information 🙂

Thanks in advance!

Edit :
Ok so now i can display my form field in the shortcode, thanks to mmm :), Now i need to display the value of it in my post.
Here the code who add my form field :

add_action("plugins_loaded", function () {

    if (!isset($GLOBALS["shortcode_tags"]["wpneo_crowdfunding_form"])) {
        return;
    }

    $original_callback = $GLOBALS["shortcode_tags"]["wpneo_crowdfunding_form"];


    add_shortcode("wpneo_crowdfunding_form", function ($attr, $content, $tag) use ($original_callback) {

            $original_result = $original_callback($attr, $content, $tag);

            // customise the HTML result of the form

            $str_to_search = "<div class="wpneo-single"><div class="wpneo-name">Short Description";

            $str_to_insert = '<div class="wpneo-single">';
            $str_to_insert .= '<div class="wpneo-name">'.__( "Describe the team" , "wp-crowdfunding" ).'</div>';
            $str_to_insert .= '<div class="wpneo-fields">';
            ob_start();
            wp_editor( $short_description, 'wpneo-form-team-description', array('editor_height'=>200) );
            $str_to_insert .= ob_get_clean();
            $str_to_insert .= '<small>'.__("Put Here Team Description","wp-crowdfunding").'</small>';
            $str_to_insert .= '</div>';
            $str_to_insert .= '</div>';

            if (strpos($original_result, $str_to_search) !== false) {
                $posToBegin = strpos($original_result, $str_to_search);
                $original_result = substr_replace($original_result, $str_to_insert, $posToBegin, 0);
            }

            return $original_result;

        }
    );


});

And here the code where i want to display it :

add_filter('wpneo_crowdfunding_default_single_campaign_tabs', 'add_tab_crowdfunding_team', 20);
function add_tab_crowdfunding_team($arr){
    $arr['test_tab'] = array(
        'title'     => __( 'The Team', 'wp-crowdfunding' ),
        'priority'  => 10,
        'callback'  => 'team_tab_view_callback'
    );
    return $arr;
}

function team_tab_view_callback(){
?>
<h1>HERE THE CONTENT I WANT TO DISPLAY</h1>
<?php
}