A .htaccess (hypertext access) file is a directory-level configuration file supported by several web servers, that allows for decentralized management of web server configuration. They are placed inside the web tree, and are able to override a subset of the server’s global configuration for the directory that they are in, and all sub-directories. [Wikipedia]
1. Login to the cPanel administration page. Find and click on File Manager. Browse to below directory and you will locate the .htaccess file there.
You can also find the .htaccess file
1. Right click on the .htaccess file and click Code Edit from the menu.
2. Alternatively, you can download the .htaccess to your local drive, do the editing and upload it back to the server.