Animations and slide transitions cannot be reproduced in the exported PDF.
Objects that you place outside the slide to make them appear on the slide via animation are not exported to the PDF. If you want these objects to be in the PDF, place the objects at the desired position within the slide before exporting the PDF.
Note: If objects are placed outside the slide, axesSlide uses a limited PDF export. You can find out more about this under Message "Limited PDF export".
Additional tips for your accessible PowerPoint presentation (not relevant for the PDF): Use animated objects and slide transitions sparingly and allow them to last a maximum of 5 seconds. Do not use animated GIF images as they cannot be paused.