In the Paragraph box under the Home tab is where the Borders and Shading buttons are located. The shading button is the one with the paint bucket pictured on it and borders is next to it on the right.
As shown in the image, clicking on the down arrow next to the paint bucket opens the color box, which displays Theme and Standard colors, No color and More colors, just in case the color you are looking for is not shown in the color box. As you move your mouse over each color, that color is previewed as the background color of the paragraph your cursor is located. The color will fill the whole paragraph or, part of the paragraph by selecting the text you want the color to fill the background with, then selecting the color. This is similar to highlighting. However, a couple of differences are that there are many more color options with shading and when shading with a dark color the text color will turn white so it is visible.
The borders box allows you to insert lines and borders in a variety of options that are self-explanatory in the drop down menu: top, bottom, outside, etc. At the bottom of the menu are three additional options. Choosing Borders and Shading opens the dialogue box offering greater flexibility in creating borders and shading in your document. There are three tabs, Borders, Page Border and Shading. Making changes under Borders will affect either the paragraph where your cursor is located or to text that is selected before opening the dialogue box. Selecting Page Border is similar to Borders with one additional option to choose from and that is Art. Clicking on the down arrow next to Art shows both color and black & white borders that can used, from apples to a dashed border with an image of scissors cutting the line. Changes made here will be applied to either the whole document or, you can choose a section and also include or exclude the first page of that section.
While different options are chosen the Preview window shows how those choices will look when applied. Within the Preview window are four buttons that allow you to add or remove just the top, bottom, left or right borders. To show some of the options available, I selected Shadow under Setting adding a drop shadow to my paragraph. Then I decided to get a little crazier -- for demonstration purposes only -- and added the dashed line for the Style, red for the Color, and adjusted the width of the dashed line to 1 ½ pt. I also selected the Shading tab and chose light tan for a background color. Shading also offers patterns that can be applied to the background, that even for demonstration purposes were too much to add!
In both the Borders and Page Border dialogue boxes are Options and Horizontal Line buttons. Options allow you to adjust the spacing between borders and text, and set margins from either text or the edge of the page. As you can see in my sample image the top and left margins were increased. The Horizontal Line button opens another window with a selection of decorative lines to choose from including squiggly, colorful leaves, and a line of rocks to name a few. If you are looking for something in particular there is a search box and the option to search Microsoft Office online for what you are looking for. When a horizontal line is selected it will appear in your document where your cursor is located.
As always, explore and try out different options to see how they will look. Remember, that these enhancements are just that -- ways to enhance your message but not overpower it!