To set up a workflow in NetSuite for the purpose of sending an email following a specific trigger, the "After Record Submit" trigger type is used. This trigger activates the workflow action after a record has been submitted or saved. It is the appropriate choice for scenarios where the workflow needs to execute actions based on changes that have just been committed to the database, such as sending a confirmation email once a form is submitted or a transaction is completed. This trigger ensures that the workflow operates on the most up-to-date information and that any actions taken, such as sending an email, are fully informed by the latest state of the record.

References:

NetSuite Help Documentation: Workflow Triggers

NetSuite Developer Network: SuiteFlow Guide