Use an Email Received trigger when documents or requests arrive in a workflow-specific mailbox. Configure sender access, allowed senders or domains, and how the email source should be parsed.
Use an Intake Form trigger for future submitters who need to provide structured fields or files. Do not use intake forms for files that are already attached to the current Workbench request; use Workbench-uploaded files for that case.
Use Request Approval when a workflow needs a human decision before continuing. Approval steps can branch, wait asynchronously, and show up in the workflow run history.