there is no 32bit option , as looking of technology utmost appliance works on 64 bit,
now all server all will be only 64 bit towards windows 2012

1. Windows Server 2012 Datacenter: –
The Datacenter edition is designed for large and powerful servers with up to 64 processors and fault-tolerance features such as hot add processor support. As a result, this edition is available only through the Microsoft volume licensing program and from original equipment manufacturers (OEMs), bundled with a server

2. Windows server 2012 standard: –
The Standard edition includes the full set of Windows Server 2008 features, differing from the Datacenter edition only in the number of virtual machine (VM) instances permitted by the license.

3Windows server 2012 Essentials: –
The Essentials edition includes nearly all of the features in the Standard and Datacenter editions, except for Server Core, Hyper-V, and Active Directory Federation Services. The edition is limited to one physical or virtual server instance and a maximum of 25 users.

4. Windows Server 2012 Foundation:- A reduced version of the operating system designed for small businesses that require only basic server features such as file and print services and application support. The edition includes no virtualization rights and is limited to 15 users