How to Restrict the modification of custom fields by the users.

[AQIB JAVED]

Is there any way to restrict the end users that, they may not modify the custom fields.

Like, Once the issue created,  Only the default values of assignee must be able to approve the ticket. Any other user may not add himself  in the approver list, 

[Dirk Ronsmans]

Hi @AQIB JAVED ,

Field level permissions do not exist on Jira.

For that specifc use case however you could use a workflow step property to disable editing of the issue to a specific user/group/customf field.

(this is the closest you'll get to edit permissions based on a rule)

https://support.atlassian.com/jira-cloud-administration/docs/use-workflow-properties/

e.g.: jira.permission.edit.group=jira-administrators

This could also be adapted to the assignee instead of a group. You might need to test this so it still allows the approval itself but this would atleast block the editing of the issue by someone not assignee. (and thus blocking them from adding themselves on the approvers list)