In SharePoint 2013 you can set unique permissions for Folders and Items\Documents using the “Shared With” option. In this quick guide I’ll describe the exact steps required.
1. Click on the “Call up” menu or “…” of folder or documents that you need the unique permissions on. Click on “…” further as shown in Fig. below and then select “Shared With”
2. Next click on “ADVANCED”.
3. Next click on “Stop Inheriting Permissions”.
4. Click OK on the message below.
5. Now you can grant Permissions to this document.
SharePoint & CRM 