ORCID iDs are now required for corresponding authors of published papers. You can enter ORCID iDs in the submission process. ORCID is an independent non-profit effort to provide an open registry of unique researcher identifiers and open services to link research activities and organizations to these identifiers. The ORCID iD is a unique, persistent digital identifier that distinguishes an individual investigator and can be used to connect researchers with their contributions to science over time and across changes of name, location, and institutional affiliation. These free identifiers are assigned and maintained by the non-profit organization ORCID (Open Researcher and Contributor Identifier).