1. A printing apparatus connected to a network, comprising: a storage constructed to store an identifier list, in which each of a plurality of identifiers is registered in a respective layer; an obtaining unit constructed to obtain an external identifier list from an external apparatus via the network; an updating unit constructed to update the stored identifier list stored in the storage based on the obtained external identifier list obtained by the obtaining unit, in accordance with an update rule; and a display constructed to display a setting screen for setting the update rule, wherein the update rule designates a layer which includes a designated identifier to be used to update the stored identifier list when the stored identifier list is updated, wherein said updating unit updates the stored identifier list from the obtained external identifier list, using the identifier designated by the update rule set in the setting screen displayed by said display unit, wherein a job identifier and a set of identifiers are set to a job, wherein each identifier of the set of identifiers is different from the job identifier, and wherein each identifier of the set of identifiers respectively belongs to a different layer, and wherein an accounting destination to be charged for execution of the job is identified by the set of identifiers.