Table width and height are two basic properties that can be assigned to a table.
The width and height of a table determine the dimensions of the table on the page. These properties can be handy if you want to control how much space the table occupies on the page.
Width You don't have to specify a width for a table if you don't want to. But if you do, you can specify a width in pixels, or a width that's a percentage of the available space on the page.
Please note that there's a lot more to learn about table width than what is explained here. For more information, see HTML Tables II: Table and cell widths.
Height This is the height of the table on the page. Most of the time you don't have to set a height because the content in the table will force the table to be as high as it needs to be.