Once you have created a website, or have some files that you need to upload to your hosting provider. You can use their File Manager to upload files one by one. The other option, especially if you have a large amount of files is with File Transfer Protocol(FTP). FTP is a standard network protocol used to transfer files between your computer and a server on a network. You can use an FTP Client to connect.
There are some FTP clients that you pay for. There are a few free FTP clients out there. A few of the more popular FTP clients are:
Filezilla (All Platforms)
You can get Filezilla from their website. You will need to make sure you are downloading the client version, and not the server version. Filezilla will work on Windows, MacOs as well as Linux.
FireFTP (all Platforms with FireFox)
You can get FireFTP on their site. FireFTP is an addon to your FireFox. The FTP Client is ran through the FireFox browser and not separately like all other FTP Clients.
Cyberduck is only available on MacOs. If you have a Mac you can get it on their site. Once you download you can use Cyberduck on your MacOs device.
The client being your local computer where you have the files saved. The server, being your web hosting service provider.
When you are connecting with FTP, you will need some connection settings from your hosting provider. The 3 things you will need are the host, username as well as the password.
Once you have an FTP Client, the connection settings, you can connect your local PC. The FTP Client is split into 2 sides. The left side is the files on your local PC. The right side is your files on the web hosting server.
You can select the files on your local PC and upload the files. If you need to download files from the server you can select them on the server side and download them.
You can also use your FTP Client to create folders and files. You can also use it to delete files on the server. However, you will need to be cautious when you are doing this. If you delete the wrong thing accidentally there may not be a way to recover them. You will need to work with your host for that.