Add the following code in wplms-customizer.php or child theme->functions.php
add_action('wplms_after_course_description','myreview_button');
function myreview_button(){
$course_id = get_the_ID();
$user_id = get_current_user_id();
?>
<form action="<?php echo get_permalink($course_id); ?>" method="post">
<input type="submit" name="review_course" class="review_course unit_button full button" value="<?php _e('REVIEW COURSE ','vibe'); ?>" />
<?php wp_nonce_field($course_id,'review'); ?>
</form>
<?php
}