Allocation is the process of selecting the optimum carrier service to deliver your consignment. You can either carry out allocation independently of the consignment creation or create and allocate simultaneously. The workflow that you use for fulfilment will determine which of these methods works best for you.
The simultaneous creation and allocation of consignments, which can also incorporate label generation in the same process, is carried out via the Allocation Service Methods of the Shipping API. Use of this API is recommended for allocation, for reasons of maximum security and flexibility.