@ProductionManagement - You have considered the employee onboarding case, where more or less the process is organized. In most of the companies, ServiceDesk is used by the external customers too, who would want to add more details to the ticket at a later point of time, like tag more products where they are facing an issue, etc.If we capture this in the comment, then this info is lost in the comments.

It would help us admins if we can enable certain fields as editable in the customer portal as per our needs.

@Tobias Maierhofer
We used a plugin to implement this in a workflow transition.
It is possible to visualize a transition with  Workflow Actions for Jira Service Management 

So this means, this feature is that less needed by admins like us, that other companies than atlassian, did the effort and created even a plugin around the issue....

All the best @Production Management at least you could people tell there are solutions.

@Production Management, I see it a bit differently... don't think only in context of IT and developers. Jira Service Management can be used for many other areas, such as project initiation requests or, as mentioned above an employee onboarding process. These are not IT related issues and in these two examples you cannot provide all the information from the beginning as sometimes it only comes up during the process. The web portal is the place where the client should track these issues, but this is severely limited by the initial input of information. If post-processing were possible for different roles, this would significantly expand the use-cases of Jira Service Management.

 I don't think this is a good idea. Portal should be as simple as possible because it is used by people who are not IT users. If customer wants to add something to the issue he can put this info in comment and developer will add it to description if needed.

In my onboarding project there are just 4 fields on customer portal. Name, line manager, date of employment and optional details. This is what HR knows and it is enough. Of course issue has much more fields like email (we fill it on first day of employment), access rights, equipment, etc. Those who work on the process fill it when needed.

For non-IT users if there is a mistake it is easier to decline the request and create a new one with correct data.

a key feature to implement an employee onboarding process

+1 It would be great to see this and more aligned to Agile, Digital ITSM. Competitors BMC / ServiceNow already have this key feature 

+1 for this feature

This is more the removal of a feature as work was done to prevent edits on them as Jira issues are editable if the field is on the edit screen.  In the case of interest, it is not like that.

I would like to see this feature as well.