Saving a doc or txt file

I would like to save txt or a doc file in my website.

I do not want normal users to view the file(mostly the administrator only)

How can I go about saving it?

You could start here: http://www.yiiframework.com/wiki/2/how-to-upload-a-file-using-a-model

This will store my file in a folder, now how do I protect it from anyone seeing it except the administrator

Any ideas?