What happens next?

How to add a header in powerpoint
Click " view, " then " slide master.
" you can add an image or string of text to the top of each slide by adding it to the slide master. The slide master contains all of the information that will repeat throughout the presentation, such as the background and default positioning of objects, and can be edited at any point during the creation of your presentation.
On a mac, click " view, " " master, " then " slide master. " Click the first slide in the slide master view.