HTML style Attribute Definition and Usage areas as follows,

An inline style for an element is specified by the style attribute. Override any style set globally by the style attribute, e.g. styles specified in the <style> tag or in an external style sheet. The style attribute can be used on any type of HTML element (It will validate on any HTML element. However, it is not necessarily useful).

Use of the style attribute in an HTML document example as given below,

<h1 style="color:blue;text-align:center;">This is a header</h1>
<p style="color:green;">This is a paragraph.</p>