This is the primary Heading text in the document itself

You can have a secondary-level Heading, too

Or even a tertiary-level Heading, and so on

Each paragraph of text is usually in its own Paragraph element.

So you'll usually have severals Paragraphs. You can give individual words or phrases added emphasis, which usually means italicization, or you can make them more bold.

You might want a line break within a Paragraph, without starting a whole new paragraph, like right here...
and you might want a horizontal line between objects in the document, like here:

You may use multiple instances of any particular level of Heading

It's traditional practice to put some contact info for the author somewhere, so readers can give feedback.
Here is how you might do that: Christopher Dobrian dobrian@uci.edu