Why are State and City empty on my Store Address page?

On Settings → Store Settings → Store Address, State and City are filled in from your Pincode. Their boxes say "Enter pincode to fetch".

1. Type your Pincode. You'll briefly see "(looking up…)".
2. State and City then fill in by themselves.
3. Check the Country, and complete Person Name, Email Id, Phone and Address. All of these are required.
4. Click Save Changes.

If they stay empty, double-check the pincode for typos. This address also appears on your printed invoices.