Check your passport is valid for at least three months after the day you plan to return from Spain. Check any visa requirements and ensure you have yours to enter Spain if needed. Check you have the correct Covid 19 status certificates, documents or covid passport if required. While it is not essential by law, travel insurance is very important. Book your policy with a reputable firm to cover your trip. Ensure you declare any medical conditions so you are covered if you need healthcare in Spain.