The Accessibility Basics and Guidelines page outlines some of the basic items to keep in mind when creating an accessible document. This page will talk about how to accomplish those basic items using Microsoft PowerPoint. However, with PowerPoint, there is a a couple additional items to consider.
Using the Home tab in the Ribbon, you can quickly select different font type, styles, size, and color. Use the small gray arrow in the corner of the "Font" command group to open the Font Properties window for more options. You can also do this by hitting "Ctrl + D" on your keyboard. Remember not to use color alone to distinguish information.
After you add an image to a PowerPoint presentation, you can use the Picture Format tab to access the "Alt Text" pane, click on "Alt Text" in the Ribbon under the Picture Format tab. The pane will open on the right, enter a short sentence describing the image.
If you add an "icon" or picture to a PowerPoint presentation using stock images available through Microsoft PowerPoint, they will automatically include alternate text.
It is best practice to avoid stacking images in presentations, including transitions. An example would be having one picture fade out with another fading in on the same slide. When your audience wants to save a PowerPoint presentation as a PDF to print or use as a handout, or adding to a screen reader. All images are stacked on top of each other because there are no transitions in handouts or PDFs. Add a separate slide for each image and add a transition between the slides for the same effect when presenting but allowing more flexibility for your audience.
Layers making up full slide:
PowerPoint slides are made up of layers. Each layer is an item you've added to the slide, such as the title, text, or an image. Each time you add a new layer, it is put over the previous ones. The image above demonstrates adding a title, then adding your content, then adding an image. The problem is screen readers start with the top layer and read down, so the last thing you add is read first. In the example above, the image alternate text would be read, then the content, then the title.
To change the order of your layers, go to the Home tab, towards the right, in the ribbon, click on Arrange, then click on Selection Pane.
The Selection Pane opens on the right. Click and hold on an item in the selection pane, then drag it up or down. Arrange your layers so the item at the top of the slide is at the top of the Selection Pane. When your PowerPoint presentation is converted to a PDF or input into adaptive software, the slide will be read from the top down.