When you cite an unpublished work such as an employee handbook, follow the MLA format template and provide as much information as you can. 

If the handbook does not name a specific author, put the name of the organization that produced the handbook in the Author element. Then give the title of the handbook in quotation marks (since it is an unpublished work) or a description if there is no title. Provide the date of the handbook, if given. In the optional-element slot at the end of the entry, indicate the format. Here are two examples of works-cited-list entries for employee handbooks:

Brewlala Coffee and Tea. “Employee Code of Conduct.” Apr. 2018. Typescript.

Dastardly Donuts. Employee handbook. 2020. PDF.

To learn how to cite other kinds of unpublished works, read about unpublished notebooks, unpublished translations, and unpublished scripts.