HTML assumes a server-client architecture. One machine, the server, would house the resources. Another, the client, would access the resources. The two machines do not have to be compatible. Both just need to understand HTTP (HyperText Transport Protocol). A simplified setup would require only accessing the local hard drive.
One advantage of HTML is that it allows different types of systems to access the same resource in the same "logical" format. A bold font on one system could be, for example, an elevated speech level on an audio output system. The creator of the HTML document does not have to worry about this. It is all handled in the client software (Browser).
All HTML 3.0 documents consist of structures called elements. They all have the same basic syntax: