How do I send automated consent emails?

I’ve been setting up Campaigns for a client (who is on Zoho One) and he deals with lots of clients over the phone. He wants to ask ‘would you like to receive our newsletter?’ and then if they do he’d tick a box in the CRM that would update Campaigns and send the person a confirmation email. That way he could confirm their address and get permission to send to them in Campaigns. He also gets new records adding to the CRM from other sources, such as Zoho Forms, that would also need a consent email sending to them.

I’m sure that this was possible in the past. Couldn’t it be done through Workflows or an Automatic Consent Email option? I can’t find the way to set this up. If the options have changed, is there another way to do this (without waiting a month before sending on mass)?