The rulers have no effect on formatting. They are a tool to display some of current formatting and let you change it. What is affecting formatting is the paragraph formatting, perhaps set in a style.

Learn styles.

• Importance of Styles in Word
• 3. Using Styles to Format Text by Shawna Kelly
• Basic Formatting in Microsoft Word

P.S. You do want to leave them turned on so you can see some of that formatting. Word's Reveal Formatting Codes