I can’t add a footer/header to the slides in PowerPoint

To fix this issue follow these steps:

1. In PowerPoint enter the master slides and once there select the first one, the parent slide. In the top action bar the Master Layout icon will be active, click on it and in the appearing window check all the options.
2. Then select the master layouts where you want the footer/header to appear and check the slide footer and header options that appear in the top action bar.
3. You can now exit the master slides view and insert your content in the footer and header of the presentation.