Although Word has a formatting feature that adds horizontal lines easily, inserting a vertical line down the middle of a page takes a bit more effort: you have to insert the line as a special shape. Fortunately, Word lets you control the line's location, angle, style, color, relation to text, alignment and thickness and even add special visual effects such as outlines, shadows and 3D appearance.
Click the Insert tab.
Click the Shapes icon in the Illustrations group.
Click the line icon, the leftmost option under the Lines heading; this icon is a simple diagonal line.
Click where you want the line to begin—for example, at the top center of the page. Holding down the mouse button, drag to the spot where you want the line to end—for example, at the bottom center of the page. Release the mouse button.
Immediately after you place the line, Word will display a special Format: Drawing Tools tab. You can use the tools on this tab to manipulate the line's style, appearance and position.