I must create a permission, at Sharepoint Online with only Add element permission, not add and view permission to element. I could create only add permission on Farm server, but I haven't create this permision on Sharepoint Online. How could I do it ? Please Help.
SharePoint gives the possibility to customize the permissions on list level. it's possible to set permissions (roles) to single users or groups. There is also the possibility the create a new role with custom defined permissions.
Go to the Home WebsiteSettings (http://portal/_layouts/15/settings.aspx) -> Website Permissions (http://portal/_layouts/15/user.aspx)-> Permission Levels (http://portal/_layouts/15/role.aspx) -> Add Role.
By adding a new Role you can specify what a role is permitted to do. In your case add only the