HTML elements are nothing but HTML tags, for example, The title tag, it represents the title of the document.
Most html elements are written with a start tag(Or opening tag) and an end tag(or closing tag).
Html elements with no content are called empty elements. Empty elements do not have an end tag, such as the <br>,<hr> elements
Element or Tag can also contain attribute that define additional properties of an elements.
for example, a paragraph tag which can have the attribute class.
ex. <p class="foo">This is paragraph.</p>
Are HTML tags Or Elements are case sensitive?
No, HTML tags or its attributes are not case sensitive. It means the tag <p>, and the tag <P> define the same thing in HTML which shows the paragraph.
Note: We recommend using lowercase for tag and attribute name in HTML.
In HTML few tags or elements are not have closing tag such elements are called empty elements or tags.
<br> tag this represents the line break.
Nested HTML Elements
HTML elements can be nested(elements inside elements)
All HTML documents consist of nested HTML elements.
<!DOCTYPE html> <html> <body> <h1>This is First Heading</h1> <p>This is first paragraph.</p> </body> </html>
<html> defines the whole document that contain <body> tag.
<body> element define the document body.
Inside <body> <h1> and <p> tags are the nested tags.
<h1> define the heading.
<p> define the paragraph.