When it comes to fields, it is usually sufficient to select which ones will appear on a given screen but Jira administrators have other options available to them. Administrators have the ability to hide fields if they wish to prevent users from changing a field's value. They also have the option to require users to provide a value for a designated field. And finally, there are a few options available for text field rendering. Regardless of the specifics, configuring a field's behavior often comes down to how the it is being used and the nature of the data it contains.
Determining field visibility comes down to one question: should users be manipulating the value in the field?
Consider a scenario in which an issue's component is set during creation as part of its workflow. The administrator may decide to hide the component field in order to prevent inadvertent changes. An important distinction to make here is the difference between hiding a field and not including it in a screen. In order to assign a value to a field, it must be included in the screen... but it does not need to be visible.
In contrast, it may be necessary to require users to enter a value for a field in some cases. For example, Jira Service Desk issues may need to be associated with client accounts. A word of caution though, requiring field values should be done sparingly. If the purpose of a required field is not obvious, or not always relevant, users may end up entering some useless text.
There is hope, though! If a text field requires a user-provided value, as opposed to one set in the workflow, it can be configured to use either the autocomplete or select list renderer. This approach can help users find an appropriate value for the field while reducing the potential for useless entries.
While the majority of fields will be visible, optional, and allow any value, it is helpful to know what possibilities are available to an administrator. Effective use of of the available options can make everyone's Jira experience a bit easier.