The recap tells the brand that its product reached your moment. Each brand asks you 4 quick questions about your own experience: whether it was your first time trying the brand, how the product was, how you feel about the brand, and whether you'd buy from them. It is not a content request, and it is not a check on you.
You'll get the questions in your recap, after your event, or for creators, once your order is delivered. It has two short parts: photos first, then questions.
On onbrand, the recap screen is called "Your recap" and the button says "Start recap". Some emails also call the recap "verification". Connecting your social accounts is a different step. It is not part of the recap.
Related: What Is Verification? · What Is onbrand?