Anyone tell me how to visualize that div element in html??

Answer 1

you can set a width, height and background-color in css and it should show up.

Answer 2

It's a block element so imagine a block. It becomes a rectangle whenever width>height or vice versa.
Background-color is the color of your block element. Padding is the distance between the edge of the shape and the content within the tag.

I hope my answer suffices. I'm not sure if I properly interpreted your question.