1. Rename ht.access to .htaccess in both your MODx installation directory and in the manager directory. If your MODx installation is in a subdirectory of your web space root, edit the .htaccess file and add the subdirectory to the RewriteBase line; for example:
2. Turn on Friendly URLs in the Configuration. You can specify any prefixes and suffixes you want here; by default there is no prefix and the suffix is .html; you can have them both empty if you don’t want any at all. You can also specify "friendly url paths", which will make a link indicating the path to a given document (yourdomain.com/news/latest_news/newsarticle1).
3. Give all of your documents URL-legal aliases. If you don’t want to do this, you can either accept the document ID as the link (mydomain.com/42) or in the Configuration tell MODx to generate a proper link out of the document’s page title.
MODx will generate the proper URL for a document using all of these settings.
If your site is served by IIS or some other web server that does not use .htaccess files, you’ll have to determine how you can do URL rewriting with the server you’re using.