If you want fixed whatsapp icon in sidebar so use below code :
Step 1 : ut below code in footer.php
<div class="fsi">
<ul><li>
<?php
if(osc_is_ad_page()) {
$rac_url = osc_item_url();
$rac_title = osc_item_title();
} else {
$rac_url = osc_base_url();
$rac_title = meta_title();
}
?>
<a style="#25D366" href="whatsapp://send?text=<?php echo $rac_url; ?>" data-action="share/whatsapp/share"><i class="fa fa-whatsapp"></i></a>
</li>
</ul>
</div>
Step 2 : Open your style.css and put below code in style.css
.fsi ul {
font-family: "Quicksand", sans-serif;
font-size: 1em;
line-height: 1.6;
font-weight: 600;
margin-left: -30px;
list-style: none;
position: absolute;
top: 50%;
left: 0%;
-webkit-transform: translateY(-50%);
transform: translateY(-50%);
}
.fsi ul li a {
display: block;
margin-left: -2px;
height: 60px;
width: 60px;
border-radius: 0 25px 25px 0;
border: 2px solid #000;
background: #FFF;
margin-bottom: 1em;
-webkit-transition: all .4s ease;
transition: all .4s ease;
color: #2980b9;
text-decoration: none;
line-height: 60px;
position: relative;
}
.fsi ul li a:hover {
cursor: pointer;
width: 180px;
color: #fff;
}