EAD (Encoded Archival Description) is an international standard maintained by the Library of Congress and the Society of American Archivists. This standard creates finding aids that standardise descriptions and the organisation of archive material.
EAD is closely modelled on ISAD(G) and is also compatible with MARC.
For more information on how these standards relate to each other, see https://www.loc.gov/ead/tglib/appendix_a.html#a2
For more information on the EAD standard, see https://archiveshub.jisc.ac.uk/ead/
EAD and Vernon CMS
Vernon CMS can use XML export to output your data into the EAD format.
For more information on how to export into EAD see XML Export and Standards.