Watermark

To add a watermark (or page background image), your section needs a header reference. After creating a header, you can use the addWatermark method to add a watermark.

<?php

$section = $phpWord->addSection();
$header = $section->addHeader();
$header->addWatermark('resources/_earth.jpg', array('marginTop' => 200, 'marginLeft' => 55));

The ODText writer preserves the watermark image in the section's ODF master page header as a page-anchored drawing frame, including its size and margins. ODF master-page headers provide the native background-like placement; exact WordprocessingML layering semantics are not portable across ODF consumers.