The submitter name is stored in the following variable: $FFwfJob.submitterName$
It's value is based on the following:
Submit Job UI - set to the logged in user’s User Name
Hot Folder - set to the Hot Folder Name
JMF - set to the AgentName
To use this value in the Sender attribute in both Core Reports and at the DFE, use the above variable as the value for this attribute in the Printer Destination Job Ticket Defaults