Answer:
1) In Normal view, on the Home tab, click Layout.
2) Pick a layout that best suits the content of your slide.
3) On the View tab, click Slide Master.
4) The slide layouts appear as thumbnails in the left pane below the slide master.
5) Do one or both of the following:
- Click the layout you want and customize it. You can add, remove, or resize placeholders, and you can use the Home tab to make changes to fonts, colors, and other design elements.
- Click Insert Layout to add a new slide and format it.
6) Click Close Master to stop editing layouts.
-Your revised slide layout will be available to insert as a new slide anywhere in your presentation.
7) Click Design and point to any theme.
8) Click the down arrow under that appears under the themes panel.
9) Click Save Current Theme, give the theme a name, and click Save. Your new theme will contain your newly revised slide layout and will be available in Themes gallery.