whatsapp：//发送？文字在Chrome中不起作用

<div class="wp sb-icon"> 
    <a href="whatsapp://send?text From 
<?php
$n=$_GET['by'];
echo "*$n*"
?>
&#10;

%20Created%20Something%20Special%20Only%20For%20You%20Touch%20The%20Blue%20Line 
<?php echo $actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]"; ?>" 
        target="_blank" title="Share this post on Whatsapp" class="whatsapp"> 
        <i class="fa fa-whatsapp" aria-hidden="true"></i> Whatsapp 
    </a> 
</div>

I am trying open WhatsApp app in a phone but it's not working through Chrome

Try this - you need to url encode all that is part of the URL. I am not sure what

<?php echo $actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]"; ?>

is supposed to do, perhaps you can show the expected end result ?

<?php $n=$_GET['by']; 
$actual_link = "http://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]"; ?>
<div class="wp sb-icon"> 
    <a href="whatsapp://send?text%20From<?=*$n*?
    ?>%0A%20Created%20Something%20Special%20Only%20For%20You%20Touch%20The%20Blue%20Line%0A<?= $actual_link ?>" 
        target="_blank" title="Share this post on Whatsapp" class="whatsapp"> 
        <i class="fa fa-whatsapp" aria-hidden="true"></i>Whatsapp</a> 
</div>