If the U.S. federal government issues your document and you need to use it in Spain, the U.S. Department of State must apostille it. The process isn't complicated, but each step matters.

Before you do anything, make sure you send your document to the right place. Documents that U.S. federal authorities issue need a federal apostille, like an FBI background check or a federal court document. State offices cannot apostille these.

If your document comes from a state (like a birth or marriage certificate), then this process does not apply to you. Getting this step right saves you time and avoids rejection.

This step ensures your document meets the requirements before you send it. The U.S. Department of State accepts official, original, or certified documents. As an example, if you submit federal court documents, the federal courts must issue them. If you send a copy, printout, or document with incorrect certification, you will receive it back without an apostille.

This form DS-4194 tells the Department of State what you're requesting and where the document will be used. You'll need to provide basic details like your name, contact information, and the country where the document will be used (Spain). You'll also list the type of document you're submitting. It's a simple form,m but accuracy is crucial; any mismatch between the form and your document can slow things down.

Now you combine everything into one complete package. This includes your document, the filled form, payment, and a return envelope. Included in one envelope: your original FBI report or federal document, completed DS-4194 form, correct payment (check or money order), and a prepaid return envelope with your address. Do not staple 

Once your package is ready, you send it to the U.S. Department of State in Washington, D.C. There are four ways to submit your application:

• By Mail: Send your Federal documents like FBI checks, court records, or anything, with the form DS-4194 payment, and a prepaid return envelope to the U.S. Department of State in Virginia.
• In-Person Drop-Off: Submit your completed form, original document, and payment in Washington DC to get faster processing.
• Emergency Appointment: Provide proof of urgent travel or a life-or-death situation to receive same-day processing if approved.
• Third-Party Service: Use a professional agency to handle submission of documents, payment, and tracking on your behalf.

Once you get your apostilled document, get it translated into Spanish by a certified (sworn) translator. This makes sure it has legal validity and acceptance by Spanish authorities for visa legal processes or consulate submissions.