The CSS Box Model essentially is a box that encapsulates content within an element, such as a div. The CSS Box model contains the "Content", "padding", "border", and "margin".
Margin clears an area around the border. If you had multiple boxes with that had a margin of 15%, each box would have a space between each box
The height increases the height of the element block vertically and the width increases the width of the element block horizontally, without changing the padding or border of the element block.
Padding 25px 50px increases the element block 25px vertically and 50px horizontally while porportionally maintaining the original position of the content
Both border and outline are essentially the same except the border surround the padding and content, while the outline encapsules everything inckuding the border, almost acting as a second outer border.