Science

You have many options in front of you if you want to pursue writing after high school. One of these options is a course in journalism which would mean you would have a license to practice journalism. You could also take up writing courses like creative writing from symbiosis or diploma in writing from IGNOU. You could also become a certified content writer and enter the industry with viable certifications.
Apart from all these options, you could also publish technical journals which are highly paid in the industry, however you require a great amount of expertise to write journals. You could start by writing blogs, articles to gain some practice and a foothold in the industry. You could start by writing for yourself, and graduate to writing as a professional.