How to Add Horizontal & Vertical Lines in Excel
One little-known feature of Microsoft Excel is the ability to draw lines on top of your spreadsheet. Although you may already be familiar with horizontal and vertical borders, they are limited to the grid housing individual cells. However, you can place drawn lines anywhere on the spreadsheet, and even drag them to a new location. Although the line tool doesn't restrict you to horizontal or vertical lines, you can force the line to be either orientation by pressing the "Shift" key.
Open Microsoft Excel and click the "Insert" tab.
Click "Shapes" in the Illustrations group and click the first icon under "Lines." This is graphically displayed as a diagonal line without an arrowhead.
Hold the "Shift" key down.
Click anywhere on the spreadsheet and drag your mouse pointer up or down to draw a vertical line. Drag your mouse pointer left or right to draw a horizontal line.