Word 2013 & 365 In Pictures
Modify a style

1 Scroll back up to the top of the document, and highlight the word Overview.

The Heading 2 style should be selected:

2 Make the text Arial.

3 In the Ribbon, put your cursor on Heading 2...

...and right-click the drop-down arrow that appears to the right of it.

In the menu that appears, click Update Heading 2 To Match Selection.