If you do need visa, the organization will be pleased to give you a letter of invitation for your application. The invitation letter issuance is subject to the registration to the conference.
Visa applications are to be done to the nearest embassy or consulate of Spain to you. Visa applications requirements and documents needed are to be requested from the concerned Spanish embassy or consulate. For the list of Spanish diplomatic missions in the world, please check this link.
For further information about the Schengen Visa Information, please check this link.
Please be aware that we won't be able to contact directly consulates or embassies and we do not intervene in anyway with the Visa process as the participant is the sole responsible to apply and follow up on his/her Visa application.