The Project Settings page can optionally be used to restrict the list of workflow states within which an issue may be signed, and which users can sign an issue. By default Signatures are permitted for all editable issue states for all users with Edit access to that issue. (see Advanced Configuration for information on making workflow states read-only)
To enable the Issue State restrictions select the issue states that the issue must be in for a signature to be applied. To revert to default settings, de-select all state fields in the list.
To enable the User Field restriction selecting one or more fields that the user must be listed in one of those fields to execute a signature. The User Fields list includes all built-in or custom user fields (single-select or multi-select) in the Jira instance. To revert to default settings, de-select all issue fields in the list.
A warning message with the restriction reason will be displayed in the Execute Signature dialog (and the Execute Signature button will be disabled) if the current issue is not able to be signed:
To revert to default settings, de-select all issue fields in the list.