The form will need to be filled out within 48 hours of their flight and passengers will need to give details about their stay in Spain.
Introduced on July 1, the form asks incoming passengers about their health and travel history and consists of five sections.
It requires your passport number, information about your flights, where you will stay in Spain and your email address. Passengers will also need to know where they are sitting on the plane.
After the digital form has been filled out and submitted, passengers will receive a personal QR code which you must carry with you, either on your phone or printed.
Arrivals in Spain will also face temperature checks and visual inspections at the airport and if they fail any of these tests, they will be required to see a doctor immediately.
Despite the Foreign Office still advising against all non-essential travel, hundreds of Brits have flown to Spain this week.
The government is expected to announce a list of countries the UK has formed air bridges with this week (slated to include Spain), which will allow for quarantine travel.
You can find the details of the form here.