I'm an Indian Citizen and I'm planning on attending a 3 day conference in Portugal, but spend another 10 days in Spain and Portugal as a tourist. Which visa type should I apply for - business or travel?
In your application you just state that after the 3 days conference in Portugal (main purpose of visit) you would like to spend a further 10 days for tourism in Portugal and Spain.
A business visa (when needed) always includes a visitor visa. So if for a conference a business visa is required, just add the itinerary for the tourism portion in the application.