How to make the close button?

https://nashvybor27.ru at the very bottom blue button to participate...and close button in the form x...How to put in the corner to white?positioning turns, but pona is obtained UNDER the blue button...and instead of the letter x, how to make a cross?

<div class="backform-item">
 <div class="backform">
 <a class="popmake-2884 pum-trigger" style="color: rgb(255, 255, 255); cursor: pointer;" href="#"><br>
To participate in the exhibition fair</a>
</div>
 <div id="clear_1" class="delete"><h2>X</h2></div>
</div>
<?php wp_footer(); ?>
the <script>
$('.delete').click(function(){
$(this).prev().remove();
$(this).remove();
});
</script>

hypertext markup language

.backform-item {
position: fixed;
top:90vh;
right:90px;
z-index: 2;
text-align: center;
}

.backform {
width: 290px;
height: 70px;
background-color: #00a7eb;
border-radius: 0px;
position: fixed;
top: 93vh;
right: 83px;
z-index: 1;
}

CSS

if you want