please tell me how to get all categories and forums with url
Uh, yourforum.com/index.php ?
I don't understand the question, sorry.
function or loop in tamplete that return all categories and forums with url
You could do a simple plugin that looped through the mybb_forums table and echo the results:
$query = $db-simple_select("forums","fid,name");
while($row = $db->fetch_array($query))
echo '<a href="forumdisplay.php?fid=' + $row['fid'] + '">' + $row['name'] + '</a><br />';