I want to ask a passport and what is essential?

Hey Angela Your Question is not Clear ..Whether you are Asking What Passport Means or What Documents are Needed to Make a Passport.
Anyways ,

If your Question if What Passport Means , Then According to Wikipedia:--

A passport is a document, issued by a national government, which certifies the identity and nationality of its holder for the purpose of international travel. The elements of identity contained in all standardized passports include information about the holder, including name, date of birth, gender and place of birth.
A passport does not of itself entitle the passport holder entry into another country, nor to consular protection while abroad nor any other privileges. It does, however, normally entitle the passport holder to return to the country that issued the passport. Rights to consular protection arise from international treaties, whilst the bearer's right to return to the passport's country of issue depends on the laws of the issuing country. A passport does not represent the right or the place of residence of the passport holder in the country that issued the passport.

2.If you want to Know What Documents are Needed for Applying a Passport :--
Every Other Country Differs in Documents that need to be Submitted for Applying for a Passport .
( My Assumption is that you are a Chinese Girl )

I Heard from a From of mine that it is not hard for getting a  Passport in China . All you need is a Your ID CArd , Hokou And May be Birth Certificate is Needed i am not Sure ..Hope Other Will Answer this .

And You can Receive Your Passport within 10 Days - Atleast my Friend got it .