I am using a basic html structure for my PDF template together with <htmlpagefooter>
according to the mPDF docs.
A sample implementation can be found here
<html>
<head>
<style>
.mydiv {
color: red;
}
</style>
</head>
<htmlpagefooter name="myfooter">
Page {PAGENO} of {nb}
</htmlpagefooter>
<sethtmlpagefooter name="myfooter" value="on" />
<body>
<div class="mydiv">
This is my PDF file
</div>
</body>
</html>
When I generate my PDF it will refuse to show the footer on any page. When I put PHP code inside it will throw an appropriate error proving that it is parsed into the mPDF.