The Chamber of Commerce and Industry provides us with the Import-Export Document Guide, which presents the forms and documents most used by the average Spanish importer and exporter in different international commercial operations.
The guide is particularly useful to SMEs starting out abroad as it familiarises them with the documentation involved in exportation: commercial documents, shipping documents, goods insurance documents, customs documents, purchases-sales in the EU, etc.
And it is all available on-line free of charge with a 24/7/365 information service.
Import-Export Document Guide 