stay in japan as business owner/freelancer

i currently have a working visa but now i want to start my own business instead or do freelance. what can i do with my visa if i quit my job but i still want to stay in japan.

You would have to change your visa to the appropriate type to cover your new profession. Business owners and freelancers are not covered by the same resident status so how you proceed depends on what direction you end up taking with your career.

if i will just file as a freelancer? what kind of visa should i get?

Last I looked you need to be able to show that you have sufficient contracts in place to pay you an income - that is hard for freelance work.

And on freelance, I believe you need to have had some years on work visa, AND then show that you have a few different sources of income/contracts to make a living. But as far as I know, those non-Japanese doing freelance work in Japan have other family related resident status such as spouse of Japanese national.

If you want to set up your own business, that would be investor/business manager status, which come with some conditions.