When you sign up to be self-employed or autónomo in Spain you have to state what sector or industry you’ll be working in, depending on your career or business. But what happens when you cross over industries and want to work in more than one?
Source : https://www.thelocal.es/20230530/self-employed-in-spain-what-are-the-tax-obligations-if-you-do-two-or-more-activities