Stepping out of the 9 to 5 and become self employment to run a business or work for yourself is a big step. Suddenly you’re expected to do all your own marketing, accounting, deal with customers directly, and make the tea!
It’s a good idea, particularly with more technical areas like marketing and accounting, to take an online course when you start, so that you understand how to market your business and the basics of accounting and business planning, and what you’ll need to do to grow your business.