Get all Styles in Office 365 Word Document
Lishani, thank you for your suggestions. We really appreciate it.
Listing all styles in the document is a gap in the Word API and we’re reviewing this suggestion right now. We’ll keep you posted.
Hope this helps!
Office Extensibility Team
Cindy Meister commented
FWIW it's at least possible to get the styles from a document using OOXML. What's not possible is creating and modifying styles. That should have a higher priority IMO.