Iframe can be defined in HTML tag The by using <iframe> tag and it can appear anywhere in your document. The <iframe> tag defines a rectangular region within the document in which the browser can display a separate document, including scrollbars and borders. iframe stands for inline frame and have src attribute which is used to specify the URL of the document that occupies the inline frame.
<iframe src=URL
>Content</iframe>
You can apply iframe element to any element and use any where within a HTML document.
If your browser does not support <iframe> element then the message inside <iframe> element will be displayed. Iframe is a pair tag and output of iframe element is rectangular frame like you can see in above example.
Open notepad or any other text editor, follow the following points.
save file with name task.html or task.htm and then open it using any browser and see results.
Don't forget iframe is non empty element which means it always comes in pair.