Welcome to the forum.
To live and work in NZ you need a suitable visa and the first port of call is the Immigration New Zealand website at www.immigration.govt.nz
Everything you need to know can be found here.
Unfortunately it isn't just as easy as deciding you want a work visa.
You need to make a decision as to your desires of living and working in NZ permanently or temporarily. If permanently you can go down the route of a temporary visa first and work towards a more permanent visa later or you can go straight for the permanent visa.
If you are only thinking temporarily then one would only seek a temporary work visa.
For the temporary route you will need a job offer in NZ as that is the essential criteria for getting a temporary working visa.
For the more permanent route which is a Resident Visa application via the Skilled Migrant Category it is a points system based on your age, qualifications, skills and experience etc. For this route a person doesn't necessarily have to have a job offer, however it all depends on the points score as many points are offered if you do apply with a job offer.
In all visa cases there are a number of basic criteria that must be met - ie the person must have an adequate understanding of the English language and be able to read it, write it and speak it very well. Another is they must be physically healthy and another they must be of excellent character.
Maybe spend some time researching through the site and come back to us with any questions.