显示在页面上的PHP命令[关闭]

Unfortunately all of my PHP commands showing on page as HTML, I don't know why. I had to use it before without errors though. What is my mistake here? ..........................................................................................................................................................................................................................................................................................................................................

<html>
<head>
<title>Add items system</title>
<?php
if (isset($_POST['submit']))
{
    if(isset($_POST['yes']))
    {
        file_put_contents('ak47content.html', '<li class="li1"><img src="images/'.$_POST["image"].'.png"><span><b>Available:</b> <br>'.$_POST['available'].'<br><br><img src="images/hiks.png"><br>&nbsp;</span></li>' . "
", FILE_APPEND);
    }
    
else
{
    if(isset($_POST['no']))
    {
        file_put_contents('ak47content.html', '<li class="li1"><img src="images/'.$_POST['image'].'.png"><span><b>Available:</b> <br>'.$_POST['available'].'<br><br><img src="images/hiks.png"><br>&nbsp;</span></li>' . "
", FILE_APPEND);
    }
        
    else
    {
        echo "Please specify if it's available or not!";
    }
}
    
    
    
    
}

?>
</head>
<body>

<form action="add.php" method="post" name="all">
<b>Available:</b> <input type="radio" name="yes" value="male">Yes <input type="radio" name="no" value="male">No <br>

<b>If NOT available, so when:</b>
    <select name="available">
            <option>Soon</option>
            <option>Next week</option>
            <option>Next month</option>
            <option>Next year</option>
        </select><br>
        
        
<b>Exteriors:</b>  <select name="exterior">
            <option>Battle-Scarred</option>
            <option>Factory New</option>
            <option>Minimal Wear, Battle-Scarred</option>
            <option>Field-Tested, Battle-Scarred</option>
            <option>Factory New, Field-Tested</option>
            </select><br>
<b>Image name:</b> <input type="text" name="image"><br>
<input type="submit" value="Add" name="submit">
</form>

</body>
</html>

</div>

It's not interpreted as PHP, check if PHP is up and running! - check the file extension - make sure that php is integrated correctly with your server - try to reinstall xampp