The conditions for entry to Spain vary according to nationality. Please check with the Spanish embassy in your country about the specific papers, if any, that you personally need in order to participate in IAUS 355 in Tenerife.
When registering, you can request an invitation letter from the IAUS 355 Organisation (email@example.com). Please note that we can only give this support if you are properly registered to the conference (you do not need to pay the registration fee at the moment you register).
IAUS 355 organisers cannot take responsibility for unsuccessful visa applications, provide further help, or intervene against any decision made by the embassies.