What do I need before I can start selling?

• Ship-from address — publishing is blocked without one. It is where your shipping is priced from and the return address on labels. Settings, then Ship-from address.
• Backup card — required to buy a shipping label, and payouts do not release without one. Account, then Payouts.
• Stripe onboarding — the bank your money deposits to. Until it is finished, earnings wait in your balance; they are never lost.

You can publish with just the address and finish the rest before your first sale ships. The Sell tab shows Finish your seller setup until all three are done — tap it and it takes you to whichever is missing.