Urgent! ! What should I do if I get an American immigrant visa and write the wrong mailing address?

Check at the post office or call the embassy. Passports sent there must have a tracking code. This is an important document and cannot be sent by ordinary mail.

And if the mailing address is where you live, it will definitely be delivered. The original mailing address may be different from the address when you fill out the DS- 160 form.