Microsoft Word
Use the built-in Accessibility Checker in Microsoft. It will provide "how to fix" steps for you to follow to make your document accessible.
Google Docs
Use the GrackleDocs Extension in Google Workspace. It will provide a report with steps for remediation of any accessibility issues.
Blackboard
Create an Ultra Document in your Blackboard course and use Blackboard Ally. Ally will provide an accessibility score as well as feedback and opportunities for remediation. You can also use Ally as a tool to check an existing document's accessibility by uploading it to your course. Ally will provide the same information for a document built within Blackboard, or uploaded from another program.