Uploading document to just one user

Content

We would like to provide our employees with their specific "development" plan that has been created by their executive. How can I upload this document to just the one employee?

Let me give you an example:

The document has overall departmental goals but also individual goals, for example, work toward more engagement with co-workers. We would like to upload this document to just the one user and have only that one person see it.

Where/How do I do that?