The from-address which is used by JobScheduler if an e-mail is to be sent is specified in the configuration.
This address is used in general for all e-mails.
If you want to use an address that depends on the job or the order, then address has to be changed using the "internal API" of the JobScheduler and specified in a "pre-processing" script.
The address itself can be a string constant or can be defined by job- or order-parameters used in the job.
The job used as an example will execute a short shell script and then exit with exit-code 5.
The coding used in the "pre-processing" routine "spooler_process_before" modifies the "from address" to "email@example.com" for this job. The modification is only effective for this job.