MyBB Community Forums

Is there anyway, to navigate to a forum without entering fid at the end of a link?

like http://www.mybb.com/forumdisplay.php?fid=FORUMNAME here instead?

You can use the Google SEO plugin to change the URL formats

Any other way?

Rename your htaccess.txt to .htaccess. Then enable the SEO links in Configuration --> Settings --> Server & Optimization Settings.

It should start turning things into .html instead of .php.
The plugins just allow for a little more customisation.