How to require a user to be logged in to access files On my website I currently have a way for users to upload files.  It has been brought to my attention that these files are showing up in search engines.  I'm fairly new and this is not a desired effect.  As a way to fix this for now, is there a way I can restrict access to sites/default/filesto logged in users? Thanks!
You have to setup the private file system. You can do this on /admin/config/media/file-system. 

Next you will have to alter your field to use the private file system instead of the public file system. If this field already has data, you can use https://www.drupal.org/project/filefield_paths to migrate the files from public to private