This is a paragraph. Notice how the text above is displayed in a larger size; that's because it’s a heading, while this sentence is written as a paragraph, which is the default text size.
This can continue endlessly. Also, notice how each heading becomes smaller in size as you move down the levels of headings. For example, H1, H2, H3.
Notice how I have added spacing after each section. This is done using a line break (br), which creates extra space between elements.