Qualifications improve your chances; they do not gate the job. Level 6 is the most recognised.
Level 6 most recognisedOpen entry
Your route in
You can start without qualifications - direct entry/volunteering; a qualification improves your chances
1
Qualifications employers recognise (Level 6)
Any of these strengthens your application.
2
Where this can take you
You could self-publish in traditional print format, online or through e-books and audiobooks. You might be able to promote your work and reputation by attending literary festivals, entering competitions, writing book reviews or teaching creative writing in colleges or universities.