Here is an example of a business letter from Purdue University’s Online Writing Lab. The sample also specifies recommended margins and spacing for the letter. This is a marketing letter example ...

feedback showed one of the things people appreciated most was the map of how to format a business letter — especially the spacing. Here it is for your benefit: The most popular business letter ...

Right-click the style you want to change and select Modify. The Modify Style dialog will now open, select the line spacing among single, 1.5x or double spaced and click OK to save the changes.