Experts who are delegated by their national standards body form a technical committee that is responsible for a specific subject area. In this case TC 215 Health Informatics. They begin the process with the development of a draft that meets a specific market need. This is then shared for commenting and further discussion.
The voting process is the key to consensus. If that’s achieved then the draft is on its way to becoming an ISO standard. If agreement isn’t reached then the draft will be modified further, and voted on again.
From first proposal to final publication, developing a standard usually takes about 3 years.