honninkakuninsyorui ga hituyou desu.

It is read ほんにんかくにんしょるい.

It is a compound noun made of three parts:

• 本人 = the person themselves, the actual person concerned
• 確認 = confirmation, verification
• 書類 = documents, paperwork

Put together, it refers to documents used to verify someone’s identity.

Yes. In this sentence, 本人確認書類 functions as one long noun.

Japanese often makes formal or technical terms by putting nouns together directly, without particles in between. So instead of something like 本人の確認の書類, Japanese often compresses it into a tighter compound.

This is very common in official Japanese, especially on forms, websites, signs, and instructions.

Here, が marks the thing that is necessary.

A very common pattern is:

• X が 必要です

This literally works like X is necessary.

That is a little different from English, where we often say I need X. Japanese often focuses on the item itself rather than on the person who needs it.

So in this sentence, 本人確認書類 is the thing being identified as necessary.

Because 必要 is not a verb.

を normally marks the direct object of a verb, but 必要です is not a verb pattern like 食べます or 見ます.

Instead, 必要 is a noun-like / na-adjective word meaning necessary. So the natural pattern is:

• X が 必要です

Not:

• X を 必要です ✘

There is a more formal verbal expression, Xを必要とする, but that is a different structure and sounds much stiffer.

必要 is usually treated as a na-adjective and also as a noun-like word.

That is why you can use it in several ways:

• 必要です = is necessary
• 必要な書類 = necessary documents
• 必要があります = there is a need

So in your sentence, 必要です is the polite predicate meaning that something is necessary.

です makes the sentence polite.

Compare:

• 必要だ = plain
• 必要です = polite

On notices, websites, forms, and customer-facing messages, です is very common because it sounds appropriate and professional.

It does not add a separate meaning like need by itself; it just makes the statement polite and complete.

Yes, 本人確認書類は必要です is also possible, but the nuance changes a little.

• が presents the item as the thing that is required
• は makes it the topic, often with a slight sense of as for

So:

• 本人確認書類が必要です = neutral statement of requirement
• 本人確認書類は必要です = as for ID documents, they are required

In many practical situations, both are understandable, but が必要です is an especially common set phrase in instructions and official writing.

Japanese often leaves out information that is obvious from context.

In a sentence like this, the speaker does not need to say:

• you need
• we require
• applicants must provide

The surrounding situation already tells you that. For example, on a website or form, the meaning is understood from context.

So the sentence focuses only on the key information: the required item.

They are close, but not always exactly the same.

• 身分証明書 often means an ID document in a general everyday sense
• 本人確認書類 is a more official or procedural expression meaning documents accepted for identity verification

So 本人確認書類 can sound broader and more bureaucratic. It is the kind of wording you often see in applications, banking, online account setup, and other formal procedures.

Yes, it sounds neutral and appropriately formal.

It is very typical of:

• application forms
• official websites
• notices
• customer service instructions

It is not extremely stiff, but it is definitely not casual conversation. In everyday speech, people might use shorter or more familiar wording depending on the situation.