Hosting companies keep their Web servers secure by restricting access to those with a valid user name and password.
Most hosting companies have numerous customers using their Web servers. In fact, some probably host hundreds if not thousands of Web sites.
Since they are responsible for storing all of these sites, hosting companies will restrict access to their servers so that only the right people can access them. In addition, they will also ensure that one customer can't access another customer's site. This kind of security is enforced by issuing each customer a user name and password.
Before publishing, make sure you have your user name and password on hand. Also note that user names and passwords are usually case sensitive. Meaning, you must type them with the appropriate upper or lower case letters.