Website files through FTP
FTP stands for File Transfer Protocol. As the name suggests, FTP is a protocol by which you can transfer files from one computer to another. You will be using FTP to transfer files between your computer and your web server. FTP gives you the ability to perform all kinds of file operations such as renaming, deleting, uploading, downloading, browsing your websites directories, and more.
To use FTP you will need some credentials that your web hosting company will give you including username, password, and domain/IP address to connect to. If you have not received this info, call your web hosting company and ask for it.
FTP, like using a control panel is also basically point-and-click and follow the on-screen instructions but it's a little more complicated. FTP requires you to enter certain credentials (see above paragraph) and working with FTP requires a little bit more technical knowledge.
You can use FTP software or a web based FTP system.
Filezilla (totally free)
CuteFTP (free trial)
SmartFTP (free trial)
Web based FTP
You don't necessarily have to use separate software for FTP. There are websites through which you can access it:
NOTE: When working with files through FTP software, you have to open the file in a code editor and upload the changes back to the web server. On the other hand, in a control panel and web based FTP, you click on the file you want to edit and it opens for you in your browser.
NOTE: FTP usually runs on port 21