Getting Started with Essay Writing - University of California, Irvine - https://www.coursera.org/learn/getting-started-with-essay-writing
Writing in English at University - Lund University - https://www.coursera.org/learn/writing-english-university
Writing in the Sciences - Stanford University - https://www.coursera.org/learn/sciwrite
English for Journalism - University of Pennsylvania - https://www.coursera.org/learn/journalism
Obviously you should find someone one with the right background to help you revise what you write. Revising and rewriting is essential to learning to write well. Remember when you were learning the fundamentals of writing well in secondary school? You had to write multiple rough drafts? All of the same things apply here.
Another method that I suggest people consider is the method that Ben Franklin used to teach himself to write. https://contently.net/2014/08/21/voices/frontlines/ben-franklin-taught-write-clever-tricks/
And as others have mentioned, read widely.