For this we can simply clone a part of the system to another node (case A) or clone the system from single/multi-node to a multi node system (case B).
For more details please read the Metalink Note 230672.1: Cloning Oracle Applications Release 11i with Rapid Clone.

Case A :- The new node will run the same or a subset of the server types running on the source node.
- We can use Rapid Clone for doing this.
How to implement the case A:
Clone the node or the subset of servers form the source to the destination node
Prepare the source system, copy it to the new node and configure it. For more details click here (see the step 3).
Add the new node to the system
After adcfgclone.pl completes, source the Applications environment and run the following commands on the target system:

cd <COMMON_TOP>/clone/bin
perl adaddnode.pl

Note: If the SQL*Net Access security is enabled in the existing system (enabled by default from 11i10), you first need to authorize the new node to access the database through SQL*Net. See Managed SQL*Net Access from HostsManaged SQL*Net Access from Hosts in document 281758.1 on OracleMetalink for instructions on how to achieve this from OAM.

Case B: - The system will be cloned with Rapid Clone and one node will be added.

How to implement the case B:
This is a normal clone. For more details please read the Metalink Note 230672.1 or click here to see how to clone an Oracle Applications 11i system.