Why do i have to type passcode into iphone and not fingerprint?

My new phone is asking for a passcode but why won't it use my fingerprint?

Have you even got the right Iphone?
In all honesty. If you have got the correct phone, i don't know why you'd want to trust a company with your fingerprints…

Because you haven't set it up to use the fingerprint scanner.

You can choose in the settings whether you want fingerprint, passcode or nothing. If you do fingerprint, you can setup 4 or 5 different scans, some people do all fingers but thats not what you do, you scan the same thumb 4 or 5 times, thats way more accurate when validating!