Multple Categories Checkbox

Hi guys,

I need some help with the following script:

<strong><?php echo __('Business Sector:*  ', 'ghh-submit-listing-plg') ?></strong><br>
            <?php
                $categories=get_categories();
                foreach( $categories as $category ) {
                    echo "<input type='checkbox' name='category' value='$category->term_id' />";
                    echo $category->cat_name;
                    echo '<br>';
                }
            ?>
            <span class="error-message"><?php echo $errCat; ?></span><br>
        </div>

I basically am displaying checkboxes and I want to be able to store all selected categories meta to the database and assign them to the post. This is the front-end: https://prntscr.com/a7sn5v

And this is how I am currently saving the meta, which is obviously wrong:

// Post Properties
$new_post = array(
    'post_title'    => $title,
    'post_content'  => $description,
    'post_category' => array($_POST['cat']),  // Usable for custom taxonomies too
    'tags_input'    => $tags,
    'post_status'   => 'pending',           // Choose: publish, preview, future, draft, etc.
    'post_type'     => 'post',  //'post',page' or use a custom post type if you want to
    'post_author'   => $authorid //Author ID
);

//save the new post
$pid = wp_insert_post($new_post);

Please shed some light on how I should go about saving multiple selected categories to the post. Any point in the right direction will be highly appreciated.