An Apache web server can host multiple websites on the SAME server. You do not need separate server machine and Apache for each website. This can be achieved using the concept of Virtual Host or VHost.
Any domain that you want to host on your web server will have a separate entry in Apache configuration file.
A helper class, a small client wrapper or a set of validation rules often starts in one project and ends up copied into the next one. From that point the copies drift apart, a bug fixed in one of them stays open in the rest, and there is no version number to refer to when something changes.
Turning that code into a Composer package removes the copies. The requirements are modest, since a package is a directory containing a valid composer.json file, a Git repository hosting it, and a listing on Packagist that tells Composer where to find it.
