Big is a formatting element used to make text large.
<big>Content</big>
Or
<tag><big>Content</big></tag>
You can apply big element to any element and use any where within a HTML document.
Big is a pair tag and output of big element is large text 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 big is non empty element which means it always comes in pair.