Input Service Distributor credit allocation must follow prescribed documentation and pro rata turnover-based apportionment. Input Service Distributors must issue prescribed documents to distribute input tax credit and may reclassify State and integrated tax for distribution. Distribution requires prescribed supporting documents, cannot exceed available credit, and must allocate credits attributable to single recipients exclusively to them. Where services relate to multiple recipients, distribution must be pro rata based on each recipient's turnover in the relevant State or Union territory during the relevant period compared to the aggregate turnover of attributable recipients operational in the current year. The relevant period is generally the preceding financial year or, if unavailable, the last quarter for which turnover details exist.