The KM3NeT Research Infrastructure will, over a period of at least a decade, produce a large amount of unique scientific data that are to be made available to the scientific communities concerned and to the broader general public. This requires the set-up of tools, procedures, documentation and rules to provide this service. For all aspects of the open data access system, including data processing methods, data structure, access and usage examples, sufficient documentation for the effective use of the open data must be provided. In this document, the documentation strategy for the different components is described.