The Attachments required validator allows you to block a workflow transition if an issue doesn’t contain any attachments.
Define the text of the error message in the Error message text field (e.g. “At least one attachment is required.”)
Activate the JQL condition option and define the JQL query that has to be met by the issue in order for the validation to work (e.g. “type = Bug and Priority = Blocker”)
Activate the Executor condition option if you want the validator to work only if the user is or isn’t in a certain Jira user group or project role
Select if The executor has to be or can’t be a member of a certain Jira user group or project role
Select a Jira user group in the Group field if Group was set in the member of a field
Select a project role in the Project role field if Project role was set in the member of a field