Microsoft has made great strides towards accessibility. They include accessibility checkers in many of their programs. The steps for most programs are included in this how-to.
Artificial Intelligence (AI) is not perfect
Please keep in mind that all in-program accessibility checkers are run by artificial intelligence. This means they are not perfect and will require human intervention, but these checkers are great tools in a journey towards greater accessibility.
Navigate to the Review menu or tab.
Word Review Menu
Select Check Accessibility.
Check Accessibility indicated on Review Menu
Click through issues to resolve them in the Accessibility Pane which will also include steps to fix the issues and reasons to fix the issues.