Not all installations of WordPress will let you edit configuration files. Let’s say, if you have a free blog on WordPress.com, you cannot edit configuration files. To do this, you need a “self-hosted” WordPress website. That means you have your own copy of the WordPress code running on your own host. Actually, that also means you’re paying a monthly or yearly fee to a hosting company or you are using a free hosting.
If You Can, Use WordPress Admin
Many files can be edited within the WordPress administration pages.
You can edit the files for a plugin by clicking Plugins on the sidebar and finding the name of the plugin, then clicking Edit.
The same process for theme files, clicking Appearance on the sidebar, then Editor in the submenu.
But not all files are available through the dashboard including the most important configuration file, wp-config.php. If you want to edit that file, you’ll need other tools.
Go to the Directory Where WordPress Is Installed
Files, such as wp-config.php, will be visible in the main WordPress directory. Other files may be in subdirectories within this directory as well. To open the directory (or folder) located on your server, you have to use a FTP client. We recommend you FilleZilla. You’ll gave to log in within the client and find the WordPress installation directory.
Within public_html, look for a directory like wp or wordpress.But you also can find the file straight in the main public_html directory. When you see wp-config.php, and a bunch of other wp- files, you’ve found it.
You can download the file, open with Notepad and make all the changes you want. How exactly to configure wp-config.php you can find here.