Science: Only exceptional late-undergraduate students, masters and PhD students may conduct laboratory research.
Law: Go to law school and pass the bar exam before you practice.
Medicine: Only medical doctors trained in university classes & clinical mentoring with a license to operate may practice medicine.
Engineering: Do a university degree, pass/survive it, and get an engineering license.
Education: Do a bachelor's degree, and education degree, and be a certified teacher.
Covid19: Epidemiologists, Doctors, Economists, Finance experts.
Islamic Studies: Uncles, Aunties, PhD in physics, engineers, social media critics and vloggers, Shamela users, Mr and Mrs I-read-a-few-books, conspiracy theorists, MSA mavericks, all welcome! It's a free for all here! Scholars? Muftis? Academics? Ijazah? Pbthhh.... That's not what the Qur'an says.