<p> tag is for paragraphs. The browser adds default spacing between each paragraph. Breaking long text into paragraphs makes it much easier for users to read. Hit them with one giant wall of text and their eyes will basically disconnect from the Wi-Fi.
html
<p>This is the first paragraph.</p>
<p>This is the second paragraph. It has space from the first one.</p>You should see
You should see two paragraphs separated by spacing.