FTP or File Transfer Protocol is one of the earliest protocols ever developed for the internet. As you might guess, FTP is used for transferring files across the internet. Most of the time, people rely on standalone FTP clients or special software programs/apps, but it is possible to use your browser as an FTP client, too.
Depending on how you installed WordPress, you may have used FTP to upload the WordPress files from your computer to the server (the computer hosting your website). If so, then you probably used an FTP client. In some cases, however, the host server already had the WordPress software available which you installed by clicking on a button.
Note: If your WordPress site is hosted on WordPress.com, then you do not have the ability to use FTP to access your files.
It is up to your web hosting provider to give you the necessary password and login credentials to access FTP. In some cases, your web hosting administration panel like cPanel will let you create your own FTP login credentials.
FTP is an alternate way to upload or access files without having to go through the standard WordPress administration screen. For example, you can upload themes, plugins, or media to your website via FTP without having to log into WordPress. FTP is also great when you have a lot of files to upload/download (like photos) or transfer large individual files (like theme packages).
Because FTP access gives you the power to delete or modify existing files, it is extremely important that you understand what you are doing before proceeding. If you overwrite or modify core files like “functions.php,” then you can permanently break or disable your site.