The xf:info element can be used for specifying meta-data such as title, author, subject etc.
Example of usage:
<?xml version="1.0" encoding="utf-8" standalone="no"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:xf="http://www.ecrion.com/xf/1.0">
<xf:info title="My Title" subject="My Subject" description="This is the description." keywords="document key word" author="My Name" />
<fo:layout-master-set>
<fo:simple-page-master master-name="all-pages" page-height="2in" page-width="6in">
<fo:region-body region-name="xsl-region-body" column-gap="0.25in" padding="6pt" margin="0.7in" />
<fo:region-before region-name="xsl-region-before" display-align="after" extent="0.7in" padding="6pt"/>
<fo:region-after region-name="xsl-region-after" display-align="before" extent="0.7in" padding="6pt"/>
</fo:simple-page-master>
<fo:page-sequence-master master-name="default-sequence">
<fo:repeatable-page-master-reference master-reference="all-pages"/>
</fo:page-sequence-master>
</fo:layout-master-set>
<fo:page-sequence master-reference="default-sequence">
<fo:flow flow-name="xsl-region-body">
<fo:block>Hello World!</fo:block>
</fo:flow>
</fo:page-sequence>
</fo:root>
This is the result in Acrobat Reader's Document Properties window: