Assuming you know the file format of the application you're exporting to, yes.
$output=fopen('outputfile.doc','w');
and use fwrite() to write out the document.
Text files, for instance, are pretty simple; for it to say:
name=Grumbler
height=180
would be something like
fwrite('name='.$HTTP_POST_VARS['name']);
fwrite('height='.$HTTP_POST_VARS['height']);
and fclose() when you're done.
But like I say, you have to know the file format you're exporting to. Everything depends on that.
Unless you want to get tricky - it may be possible to use the application itself in some fashion which I haven't the foggiest idea about - there is a PHPBuilder article involving something of the sort on Windows systems...