You can 'customize' the Organization field but it is not like other Custom fields since it is a field added by a plugin (JSD in this case). It is locked because it is manipulated using the UI elements provided by JSD. Within any JSD project you can add new Organization names i.e. usually your Clients/Customers/Company names and then you add their employees accounts to that Organization (all within the JSD project).
Although you add values to the Organization field within a project, those particular company names (and employees) to other project very easily.
In other words, it is like User management, done from within projects.
It does not make any difference whether you have a free Jira account or not.
Connect with like-minded Atlassian users at free events near you!Find an event
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no Community Events near you at the moment.Host an event
You're one step closer to meeting fellow Atlassian users at your local event. Learn more about Community Events