I got an overall 6 bands in IELTS. I want to become a chef in New Zealand. Is it possible?

Usually, the IELTS paper test is only on Thursdays and Saturdays. But the computer-delivered IELTS test often has slots on Sundays in big cities. You will get to know about the IELTS available dates while booking the slot only. 

Yes, A valid passport is mandatory. You need to upload a scan when you book and bring the original passport on the IELTS exam day. No other ID is accepted.

It is best to book at least 1 to 2 months in advance. High-demand months (like before university deadlines) and Saturday slots fill up very fast. Avoid last minute booking of IELTS slots. 

Yes, if you book IELTS on paper, you can often pick your Speaking slot during registration. For the computer test, the speaking part is usually on the same day or very close to your main test date.

Not always. IELTS Academic is available on all 48 paper dates. However, General Training is usually only available on 24 dates (about twice a month) for the paper format. On computer, both are available daily.