You need to study the Award in Education which is a level 3 qualification. You can study online or at college and there are usually lots of ways to study including intensive 1 week courses, evening classes and daytime courses. The course teaches the theory of teaching adults vocational subjects and includes a little practical work. No reputable brand or educator will accredit you without this qualification. It's the minimum requirement.
I tried to study online. The first company was a fake and I got scammed of my money. The second was excellent but I had completely underestimated the work and I struggled and in the end signed up for a 14 week course at college. It was 3 hours college plus 3-4 hours homework. I really enjoyed the college course and got far more from it than I expected. I met a load of new vocational subject teachers and made some contacts for future work. I also got far more from the course when I studied in college, I'd definitely recommend this route.
After this you can look into BABTAC accredited teaching and becoming a trainer for a brand. Try the brands you use in salon.
