Anyone can learn how to write better even if they don't take an English college class. All you have to do is look at some available options online to learn about grammar from programs on the internet. Some people who want to brush up on their writing skills take a refresher training course on putting words on paper, so they learn to write better.
Do a search; it is as simple as that. Look up sources that will show you all of the different writing courses. If you have a class asking you to write a paper about how to take a class on this that is what you should add to your essay about this. Look for classes that have exactly what you are looking for in the course. What skills are you looking for? Write down and note the specific things you need to have included in the course.
Most if not all of these training courses will cost money. What you need to do is decide how much you are interested in spending on the course. You will have to spend at least some money. There are also courses geared to people wanting to get into freelance writing. See what each program offers. They all may have different durations of time that they take to complete. Some businesses may even offer this, but again, not for free. You are not going to get writing training courses for free. It might help to include this bit of information in your school work assignment.
Give yourself time to sift through the decent course versus the ones that may not have the skills you are trying to learn. Be prepared to spend the amount of money being asked of you to take the course. It doesn't seem like these training courses should cost much if any money. If you decide to go for it look up as many courses as you can to keep your options open. The way to know if a course is really good depends a bit more on what each student needs to learn to work with a freelance company.