The Format Painter icon allows you to copy font and paragraph formatting from selected text to multiple locations in a Word document, Excel spreadsheet, Access database, Publisher file, FrontPage and a PowerPoint  presentation.
 

How to Copy Formatting to One Selection…
 Select the source text to copy. If this includes paragraph formatting, make sure all the paragraph is selected.

Click the Format Painter icon, which will change the mouse pointer into a “paint brush” with an I-beam. Sample below illustrates this in Word.

In Excel (shown below) a "dancing border" will surround the source formatting and "plus" sign will accompany the mouse Paint Brush pointer.

3.      Use the “paint brush” to select the text that you want to format. Formatting from source text will exist on selected text.

4.      Mouse pointer will return to regular appearance.

How to Copy Formatting to Multiple Selections…

Select the source text to copy.

Double-click the Format Painter icon, which will change the mouse pointer into a “paint brush” with an I-beam/plus sign.

Use the “paint brush” to select the text that you want to format. Formatting from source text will exist on selected text.

The pointer will remain a paint brush allowing you to format additional selections with the same formatting as the source text.

To turn off the painter: click Format Painter icon or the Esc key on the keyboard.