ORCID, which stands for Open Researcher and Contributor ID, is a free, unique, persistent identifier (an ORCID iD) that researchers can use to distinguish themselves, and their research. ORCID also provides a research profile that links a researcher's research outputs and activities to their ORCID iD.

ORCID is integrated into many systems used by publishers, funders, institutions, and other research-related services.

Your ORCID iD is always publicly visible.

You can control the visibility settings for all other content in your ORCID record.
 

There are three visibility settings: everyone, trusted parties, or only me.

• Everyone: Information marked as everyone can be viewed by anyone who comes to the orcid.org website or consumed by anyone using the ORCID public API. This information is also included in the public data file posted annually by ORCID.

   

• Trusted parties: Limited-access information that can be seen by any trusted parties whom you have granted access to your ORCID record. These connections require explicit action on your part.

  

  • Trusted organizations: The organization will ask you to grant them specific permission to read limited-access information at the same time that you give them permission to get your ORCID iD. Once you have granted permission, the trusted organization will be able to see information that you have set as visible to trusted parties in addition to the information set as visible to everyone.
  • Trusted individuals: You can grant any ORCID iD holder account delegate access as a trusted individual to help administer your account on your behalf. Once you have granted them delegate access, the individual will be able to see information that you have set as visible to trusted parties access in addition to information set as visible to everyone. 

• Only me: Private information can only be seen by you and trusted individuals you have granted access to help administer your ORCID record on your behalf. It is also used by ORCID algorithms to help distinguish your identity from another person who may have a similar name, be in a similar field, or may be confused with you for other reasons. This information is not shared with others.

The default visibility setting of your name when you register is everyone. The default visibility setting of your email address(es) is only me. You can immediately update the visibility of these items after registration by changing the visibility selector next to them.

You can set the default visibility setting for any new data added to your ORCID record after you register.

Source: https://support.orcid.org/hc/en-us/articles/360006897614-Visibility-settings

Your ORCID iD:

• distinguishes you and ensures your research outputs and activities are correctly attributed to you
• reliably and easily connects you with your contributions and affiliations
• reduces form-filling (enter data once, re-use it often)
• improves recognition and discoverability for you and your research outputs
• is interoperable (works with many institutions, funders, and publishers)
• is persistent (enduring)

It is also a requirement of many online submission systems for journal manuscripts and grant applications.