Summary

In Jira Cloud company-managed projects, workflows can be used so that a custom field is only editable by members of a certain group. In the example shown here, we are restricting the Original estimate field.

This guide is based on the answer provided in this community post https://community.atlassian.com/t5/Jira-Software-questions/Re-Custom-field-edit-restriction-based-on-user-role-perm/qaq-p/2032330/comment-id/535794#M535794 with thanks to its author.

Solution

1. Create a screen containing the Original estimate field. NOTE: In the screen-edit view, this field is referred to as "Time tracking":
   

2. Go to your project's workflow and click Edit. Click Add status and call the new status Edit Original Estimate. Make sure to check the box that says "Allow all statuses to transition to this one":
   
3. Click on the transition from All > Edit Original Estimate. In the screen section, select the screen from step 1.
4. Click on the transition again and select Conditions. You will be redirected to the transition edit page.
5. Select Add condition and add the permission rule you want to execute for this button.
   
   Note that this rule will control who can see the Edit Original Estimate and therefore edit the Original Estimate field.
6. Publish the workflow.
7. Remove the Original Estimate from your Edit screen. You will need to create separate "View"/"Edit" screens for your screen scheme if you haven't already because you may want the restricted field to remain visible when viewing the issue:
   

Outcome

Setting up this workflow results in the following behaviour: Members of the selected group (specified in your workflow condition in step 5) will see the Edit Original Estimate status when they click on the Status dropdown:

When they select that status they will see a screen with the original estimate field which they can edit the original estimate field:

Users who are not in the selected group will not see the "Edit Original Estimate" status as an option: