When you do, the changes appear on every slide in the presentation that’s based on that master. You can make changes to a master slide like you can to a regular slide-including modifying the appearance of text, changing the slide background, and changing the size of the images. If you want text, shapes, or images to be editable in your presentation, you must add them as placeholders to the master slide.
Here you will quickly notice that in addition to the footer, you can also set the date and the number of pages/slides. When you click on that button, a dialog will open. If you add new images, text, and other objects to a master, these objects become part of the slide background and aren’t editable in your presentation. Click the 'Insert' tab on the ribbon, where you will find the 'Header & Footer' button in the Text group. Only the slide in your presentation is changed the master slide remains in its original state. When you want to add a slide to your presentation that has particular elements-such as a title and subtitle, a bulleted list, or an image-you select the slide layout that most resembles the layout you want, then you replace the placeholder elements and make other changes as necessary. This will open a new set of slides known as Master slides. The slide layouts used in each Keynote theme are based on master slides. In Microsoft PowerPoint you just need to open the View tab and locate the Master Slide button.
