A family of Microsoft word processing software products for creating web, email, and print documents.
Sorry to hear that you are having trouble saving your Word document. Could you please provide a little more information about what happens when you try to save it? For example, when you select File > Save As, does the Save window appear, or does absolutely nothing happen? Do you receive any error message at any point?
Please also let me know which macOS version you are currently using and which version of Microsoft Word you have installed. You can check this under Word > About Microsoft Word.
Whether the problem happens with every Word document or only this particular document. Whether you can create a new blank document and save it to your Desktop or Documents folder. Whether the document is being saved locally on the Mac or to OneDrive/iCloud.
If possible, please also share a screenshot of what you see after selecting File > Save As, making sure no personal information is visible.