$re = '/page="[0-9]+".+?subject="(?:Text Box|Sticky Note)".+?<\/span/s';
$str = ' ><text color="#FFFF00" creationdate="D:20180307100631+04\'00\'" flags="print,nozoom,norotate" date="D:20180307100652+04\'00\'" name="a60915a3-1c23-4f6d-b8d4-fbe0dd4890e9" icon="Comment" page="7" rect="351.308000,135.732000,371.308000,153.732000" subject="Sticky Note" title="saddia"
><contents-richtext
><body xmlns="http://www.w3.org/1999/xhtml" xmlns:xfa="http://www.xfa.org/schema/xfa-data/1.0/" xfa:APIVersion="Acrobat:9.0.0" xfa:spec="2.0.2"
><p dir="ltr"
><span dir="ltr" style="font-size:10.0pt;text-align:left;color:#000000;font-weight:normal;font-style:normal"
>As agreed with WPO that any unspecific area use GEN</span
><span dir="ltr" style="font-size:11.0pt;text-align:left;color:#1D477B;font-weight:normal;font-style:normal"
>
</span
><span dir="ltr" style="font-size:11.0pt;text-align:left;color:#000000;font-weight:normal;font-style:normal"
>
</span';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php