@Kate2503 I am not sure what info you are being asked for but a few points below might help:
1) Some hosts (particularly for house shares) want info about a guest to check compatibility. Other hosts for whole homes want assurances that guests are not planning parties etc so look for other info.
2) Airbnb looks to verify a guests ID so that they at least know who is booking the property
3) Some listings accept bookings instantly - others require you to request a booking whereby the host has to answer the request within 24 hours. You can filter the search to only give you IB listings if you want.
4) Airbnb has an algorithm to block high risk bookings. I think this might block you if you are young and trying to book a place near where you live.
Does any of the above make sense? If not perhaps give a little more info and we might be able to help.