how to delete viewers on main page ? or hide them ?

Hi John, 

Welcome to the Box Community, I'm happy to help!

If you would like to hide the collaborators on a folder that you own, you can do this following these steps:

To hide collaborators:

1. Right-click the folder (or click the ellipsis (...)) to open the More Options menu.
2. Click Settings to open Folder Settings.
3. In the Privacy section, check the box next to Hide collaborators and their activity from non-owners.

For more details, please take a look at this article: https://support.box.com/hc/en-us/articles/360044196273-Managing-Collaborators#hidecollab

Hope that helps! 

Thanks for posting and let us know how else we can help!

Regards,