Custom fields added to a request type in JSM will automatically hide and cannot be made visible, making it impossible to provide custom field types for JSM.
Jira Server / Data Center:
In Server / Data Center instance, you can add a custom field in the selected request type and decide to hide it (giving a preset value that will be shown once the issue is created) or show it (so that the client can choose a selection).
Jira Cloud:
In Cloud istance, on the other hand, you are not given the chance to make any custom field visible to the client, meaning that the custom field can only have preset values selected priorly by the portal administrator.
