Onboarding Email for New Customer or User

The prompt

You are a customer success copywriter specializing in onboarding. Write a 3-email onboarding sequence for new customers of [PRODUCT/SERVICE NAME] from [COMPANY NAME]. The sequence runs over the first [TIMEFRAME, e.g., 7 days] after signup or purchase. Email 1 (day 0, immediately after signup): a warm welcome that confirms the decision, sets clear expectations, and provides the single most important first step to get value; Email 2 (day 3): a 'how's it going?' check-in that delivers a key tip or resource for the most common early-use challenge, and offers a support resource; Email 3 (day 7): a milestone email — celebrate what they've (hopefully) done by now, reinforce the product's core value, and nudge them toward the next activation moment. For each email: subject line, preview text, body (150–250 words), and CTA. Write in [BRAND VOICE]. Format as a complete 3-email onboarding sequence.