To register for an ORCID, go to orcid.org and fill out the form.

Open Researcher and Contributor ID (ORCID) is a not-for-profit organization, international in scope, which is developing a system of identification for scholars. ORCID identifiers are for everyone, because they aren't attached to a specific disciplinary tool or subscription. As of this writing, it doesn't cost anything to register for a personal identifier to use. The ORCID is more inclusive of a diverse range of scholars, in part because it is free, and has national and international representation. It also allows individuals to list names that they were previously identified by, and link them or work done under them into the individual's profile, which can be helpful with life or status changes.

Some campuses do have subscriptions, so if you are coming here from elsewhere, you may already have an ORCID. You should continue to use the one you have, if you do.

ORCID is gradually becoming a standard of its kind. Any of the IDs have their pluses and minuses. Different organizations will prefer one or the other, or allow either to be used. Some grant providers or publishers require their grant requestors or authors to have one type of ID or another.

ORCID identifiers start with the address of their web site: http://orcid.org/xxxx-xxxx-xxxx-xxxx, where the X's are replaced by a unique series of numbers, as shown in the image below. You can see two other examples of identifiers, one for Researcher Profile from Clarivate and one for Scopus, in the same image,

To register for an ORCID, go to orcid.org and fill out the form.

ResearcherID: C-3156-2012

ORCID and ResearcherID/Researcher Profile, as well as some other profile products, like Scopus, will allow you to enter information about yourself in one and then port it over to the other by clicking through and logging in.

Publishers to Require ORCID Identifiers for Authors

"A group of seven publishers today announced that, during 2016, they
will begin requiring authors to use an ORCID identifier (iD) during
the publication process. The American Geophysical Union (AGU), eLife,
EMBO, Hindawi, the Institute of Electrical & Electronics Engineers
(IEEE), and the Public Library of Science (PLOS) will join the Royal
Society – which already (as of January 1, 2016) requires its authors
to include iDs at submission – in making this commitment.

ORCID iDs are persistent identifiers for people. Using an ORCID iD
ensures that researchers can be easily and correctly connected with
their research activities, outputs, and affiliations. Over 200
research platforms and workflow systems collect and connect iDs from
researchers: grant application and publishing systems, association
management systems, and university CRIS and other research information
systems.

Over 1.8 million researchers globally have registered for an iD,
understanding the value a digital name provides in enhancing
discoverability and reducing their reporting paperwork. Some funders
have started to require ORCID iDs as part of the grant proposal
process, and in a recent survey researchers indicated strong support
for similar requirements by publishers."

http://elifesciences.org/elife-news, January 7, 2016