A tab stop is used in a document to line up columns. When you press the Tab key on the keyboard, the screen cursor moves to the next tab stop on the line. Tab stops are pre-set in Word for every half inch.There are four types of tabs, but the most commonly used are left aligned and decimal. Use the left tab to line up columns of names, and use the decimal tab to line up columns of numbers.Setting TabsTo set a tab, be sure the tab symbol on the left side of the ruler is set to the type you want. If not, click the symbol until the type you want is visible. Then, click the ruler where you want the tab to go. The tab stop symbol will be displayed on the ruler. After placing the tab stop on the ruler, you can move it by dragging it to a new location.