Profiles are automatically created when someone purchases a ticket or makes a payment — there is no separate "add customer" step.
What you add manually is context on top of that profile: open a customer and post a memo to leave notes for your team (e.g., a VIP flag or a support note). Memos support attachments and can be marked visible to your organization only.
Tip: Customer profiles persist across events, so you build a richer picture of your audience over time.