Output New Query from Form

Output New Query from Form

I'm trying to figure out how to make a form that changes Query Example (HTML)
<form action="change.php" method="POST" name="Update">
<table>
<tr>
<td>
<input type="text" value="Enter New Criteria" name="where" >
<input type="text" value="Enter New Criteria" name="where2" >
</td>
</tr>
<tr>
<td align="center" style="font-family:Calibri">
<input type="submit" value="Search"/>
</tr>
</table>
SQL Query
$Query = "SELECT order_number
FROM order_header
WHERE (order_number LIKE **'%CHANGE VALUE HERE%'**
OR order_number LIKE **'%CHANGE VALUE HERE%'**
How would I go about doing that, i'm a complete rookie but I am trying. I
tried a search but maybe I'm not using the correct key words.