Superscript is a formatting element used to make text upward and is used to make formulae, you can make any text in upper direction by using the superscript.
<sup>Content</sup>
Or
<tag><sup>Content</sup></tag>
You can apply supersript element to any element and use any where within a HTML document.
Superscript is a pair tag and output of superscript element is upward text like you can see in above example.
Open notepad or any other text editor, follow the following points.
Trade Mark TMto heading 3
Trade Marktext
save file with name task.html or task.htm and then open it using any browser and see results.
Don't forget superscript is non empty element which means it always comes in pair.