Block Level element:

A block-level element always begins on a new line, and browsers add a margin (a space) before and after the element by default.

A block-level element always occupies the entire available width (stretches out to the left and right as far as possible).

(<div>and<p>) are the most famous block level element.

Inline Elements:

An inline element only uses the space that is required. An inline element only uses the space that is required.

(<span>) are the most famous Inline element.

Bold/strong Tag:

It is used to bold the text.

    <b></b>
    <strong></strong>

Italic/em Tag:

It is used to Italicizes text.

    <i></i>
    <em></em>

Underline tag:

It is used to underline the text.

     <u></u>

Paragraph tag:

It is used to write paragraph.

    <p></p>

Image tag:

It is used to insert image in the web page.

    <img src="" alt="">

Anchor tag:

It is used to interlinking the web pages. href is a attribute which means reference.

    <a href=""></a>

Subscript and Superscript Tag:

To Makes text subscript and supscript.

    <p>Formula of water: H<sub>2</sub>O</p>
    <p>Area of Square: side<sup>2</sup></p>

Mark tag:

To highlight the text.

    <mark></mark>

Abbreviation tag:

To represents an abbreviation.

    <abbr title=""></abbr>

Definition Tag:

To represents a definition.

<dfn></dfn>