WordPress sites include a file with the name .htaccess. This file includes configuration information that can actually override a server’s default configuration setting. Users can modify their .htaccess file to change the server’s cache control, authorization, URL rewriting, and optimization. WordPress users are often especially interesting in URL rewriting because the default URL option is not easily read by search engines or human visitors.
One way WordPress modifies the .htaccess file is through the Settings, Permalinks panel. Here, WordPress administrators can change how WordPress creates URLs. If an option other than default is selected, WordPress rewrites the .htaccess file.
In most cases, WordPress is able to modify the .htaccess file on its own, but there are some cases where the user may have to manually make changes to the file. This is often discouraged because if the file is not edited correctly, it can lead to a wide number of server errors that may cause the site to be inaccessible. Only those who understand what they are doing should modify the file.
The .htaccess file can usually be found in the site’s root directory. However, users who access their site through FTP may need to go into their FTP client’s settings and instruct it to show hidden files, since by default any file named with a period is hidden.