Block-level elements always start on a new line and take up the full available width. Five common ones are <div>, <p>, <h1>–<h6>, <ul>/<ol> and <table>.
<div>– a generic container used to group other elements for layout and styling with CSS.<div class="card">...</div><p>– a paragraph of text; browsers add space above and below it.<p>HTML is a markup language.</p><h1>to<h6>– headings, from most important (h1) to least (h6); used for document structure and SEO.<h1>Main Title</h1><ul>and<ol>– unordered (bulleted) and ordered (numbered) lists; each item is an<li>.<ol><li>HTML</li><li>CSS</li></ol><table>– displays tabular data with rows<tr>, headings<th>and cells<td>.
Other block-level tags: <form>, <section>, <header>, <footer>, <nav>, <article>, <blockquote>, <pre>, <hr>.
Contrast: inline elements such as <span>, <a>, <b> and <img> do not start a new line and take only as much width as their content. The display type can be changed with CSS (display: block / inline).