Transactional flows work in the background to ensure that you're properly supported when managing your reviews. This means that they'll work on their own and don't need much attention from you. You can find your transactional flows here.
They should always be enabled unless you have a specific reason for disabling them, eg. doing the same task through an integration.
There are two transactional flows:
When you respond publicly to a review in the Manage Reviews section of Junip, you can choose to Notify the customer of your response. This flow will send that email to the customer for you.
When a customer submits a review that requires confirmation (eg. using the manual product review links or "write a review" button on-site), we'll need to send them an email so that they can confirm their review. More on review confirmation here.