What is the permission for Anonymous Users in SharePoint?

Here is a Article from Microsoft Technical Blog [https://technet.microsoft.com/en-in/library/ff608071.aspx#section2 ] on anonymous user's permission policy.

Hope it will help.

Firstly, you will have to enable anonymous access on SharePoint web application.

Then you can set the permission level to anonymous users.

The permission level for anonymous user can be set on

try it

http://sharepoint.stackexchange.com/questions/90012/permission-to-anonymous-user-for-document-of-document-library

mirror 1

https://support.office.com/en-us/article/Enable-anonymous-access-3647cdd5-1ab8-48cf-b4ee-d1b652bbabdd

mirror2

https://technet.microsoft.com/en-in/library/ff608071.aspx