Make sure you select the appropriate settings when saving as a PDF to ensure it’s bringing over some of the accessible items you have already built in your document.
Use the Accessibility Checker in Word to run a quick scan of possible issues within your document.
In addition to images, tables also need a text alternative if you are planning on distributing your document in digital form.
If you are using images to further explain concepts in your text (not just as eye-candy), then make sure to provide alternative text for the image that can be recognized by a screen reader.
If you have a multi-page document that utilizes headings and sub-headings, you can easily create a table of contents to display your document’s navigation.