Maybe you are a web designer, or you have an index file and want to upload it to your site. You can follow this tutorial to upload your web site files on your hosting account.
1. Open FileZilla FTP Client.
2. Enter your FTP Host, Username, and Password. You can use your cPanel username and password as your FTP User and Password and then click on the Quick Connect button.
In the Host field, You can use your domain name like ftp.example.com or example.com. 
3. Make sure that you are inside the public_html folder, If not then double click on it to go to the public_html folder.
4. Under Local Site in FileZilla, Open your folder where your index file, etc., is located and then select your index file and click on the Upload option.
The index file will be successfully uploaded.