Yes, IELTS or TOEFL is mandatory for studying in Europe. If you plan to study in Europe in a program taught in English and English is not your first language, you generally need to submit IELTS or TOEFL scores. Most universities ask for proof of English skills when you apply. But, some schools might not require these scores if you studied in English before or can prove your English ability in another way, like a letter from your old school. Since the rules change depending on the country and university, be sure to check what your program needs.