This free software is designed to recover Word file open passwords. These are by far the most common passwords in protected Word documents.
Free Word / Excel Password Recovery software is particularly effective when a common Word password, or if a fairly short password was used (long passwords can be infeasible to recover with this sort of software due to the time required).
This software won't recover VBA macro passwords (uncommon with Word files), or Word document protection passwords, but again other packages are available to do this, or you can use a service.
You can try this software which is fully featured and completely free before outlaying money on a recommended commercial package, such as Passware Kit Basic It includes more functionality than many costly commercial packages, but since it is free you are not risking anything by trying it.
If you run Windows Update regularly on your system, you should already have everything you need, otherwise you can download the prerequisites and the software from the Download page.