A web host is a place on the Internet where you put the files that make up your Web site, so they can be viewed in the web browsers of visitors as they surf to your site.
A web hosting company is a place that rents you web space to store the various files that make up your Web site. It provides the bandwidth (the measurement of data and information sent from your host's server to the computers of your visitors) needed for your Web site to be accessible to Internet surfers.
A server is a combination of software and hardware that makes it possible for web pages to be shown in commonly used browsers such as Internet Explorer or Firefox. A browser is also known as a client, so there is a client - server relationship needed for web pages to be shown to visitors.
The hosting computers (the servers, where the files that make up your site are stored) are connected to the Internet all the time, that's 24 hours a day and 7 days a week. The server computers can be found by all the other computers, such as yours, that are also connected to the Internet.
You will perform what is known as an "upload" of the files making up your site to your hosting company's server using a process called File Transfer Protocol (FTP). Your host will have an interface and dialogs that make this FTP process easy to perform. There is also software available for FTP. FileZilla is popular free FTP software. I've used FileZilla for years and recommend it.
You will be charged a hosting fee, usually on a monthly or yearly basis, for the services of storing your Web site files on a hosting server and for making your Web site available for viewing by Internet surfers. The web hosting business field is very competitive, so there are many to choose from and more plans and offerings than Carter has oats.
It's a big city out there on the Internet. There are many, many web hosts. A Google search for the term "web host" as I was writing this article brought up 175,000,000 search results. There are plenty of them to choose from. There are good hosts with good plans, and there are bad hosts with bad plans. Shop around and find the one that's best for you.
To sum up:
A web host is a place on the Internet where you put the files that make up your Web site. You need a hosting service so the files of your Web site can be kept on a server. The server is made up of software and hardware that will send your Web site files on to a visitor's browser when he or she types your Web site's name into their browser (a client). There are lots of web hosts to choose from and they have lots of different hosting plans. You will pay a fee for the web host's services, but web hosting is usually very affordable because there is strong competition amongst web hosts.