Don't answer blindly if you don't know upstairs.

ORCID is an open, non-profit and public-driven organization. It is committed to solving the problem of eliminating the ambiguity of authors' duplicate names in academic publishing activities, generating and saving the unique ID registered by researchers, and openly and transparently linking these IDs with research activities and achievements.

Every paper author will have a 16 digit ORCID. It seems that most journals suggest that you provide each author's ORCID identification code (16 digits) when submitting a manuscript. The format of ORCID identification code is: 0000-0002-3206-1091.