Here it’s explained how to change visa from not-working one to working visa.
Typically for a foreign national who has visa of student or trainee.
1. Check if you meet the requirement of any of working visa. If you have
a degree of bachelor of university or college, visa of Engineer/ Specialist in Humanities /International Services suits you.
2. Look for and find a job, and make employment contract with some company
3. Apply for change of status of residence to working visa with the employer
You get a work first, visa after.
Working visa can not be applied only by foreign national. Employer company also makes application form as sponsor.
If you have enough money, it’s an option to incorporate a company and get Business Manager visa.
It's important to meet some requirement to apply for working visa.