The phrase "form rejection" means receiving a standard or generic response to something, typically a job application, manuscript, or proposal, indicating that it has been turned down or declined. Full definition
But also thanks to the fact that agents are no longer wasting hours every month mailing and / or emailing meaningless form rejection letters. (literary-agents.com)
Whichever form rejection takes, it hurts and can be very difficult to overcome. (elitesingles.ie)
And yes, you would get the standard form rejection letters, since each agent / editor is subjective of what they're looking for. (hubpages.com)