While the detailed process of codification is not the responsibility of procurement or user authorities, it is desirable that users in particular are conversant with the codification requirement to facilitate proper introduction of the equipment being procured into service. The following paragraphs set out, in brief, the normal series of actions that make up the codification process. Flowcharts may be prepared by NATO Codification Sub-Groups established for the co-ordination of codification of major projects; however, they may also be used by any authority which sponsors or controls codification projects.

To ensure that the correct Items of Supply are codified for any given piece of equipment, the equipment designers and user community must decide on which IoS will be identified as potential spares to be eventually stocked in the inventory of the user nation. This is accomplished by the user group studying data such as the Logistics Support Analysis (LSA) and the Initial Provisioning List (IPL) created by the Main Equipment Supplier. The IPL shall be screened against the existing codification database to identify those Items of Supply which are already part of the user nations' inventory. Items of Supply which are not found in the existing database require codification. The result of this process will be a final list of Items of Supply, with NSNs and related data recorded, which are to be procured in order to support the equipment in service.