todokedenin ga sinseisyo wo kaku.

It is read:

とどけでにん が しんせいしょ を かく
todokede-nin ga shinseisho o kaku

A few notes:

• 届出人 = とどけでにん
• 申請書 = しんせいしょ
• を is written を but pronounced o
• 書く = かく

They mark the grammatical roles of the nouns:

• 届出人 が = the subject
  The person who does the action.
• 申請書 を = the direct object
  The thing being written.
• 書く = the verb, to write

So structurally, this is:

[subject] が [object] を [verb]

In this sentence:

• 届出人 is the one doing the writing
• 申請書 is what is being written

Both can mark something like the English subject, but they do not feel the same.

• が identifies who does the action
• は introduces the topic, often with a contrastive or more general feel

So:

• 届出人が申請書を書く。
  Focuses on the filer/applicant as the one who writes it.
• 届出人は申請書を書く。
  Means something more like As for the filer/applicant, they write the application form.

In an isolated example sentence, が is very natural because it simply marks the subject clearly.

Not completely. Japanese word order is more flexible than English because particles show each word’s role.

The basic order is:

届出人 が 申請書 を 書く。

But you could also say:

申請書を届出人が書く。

This still means roughly the same thing, because:

• が still marks the subject
• を still marks the object

However, changing the order changes the emphasis or flow a little. The most neutral textbook order is the original one.

It can often mean either, depending on context.

Literally, 書く means to write.
But with things like forms and documents, Japanese often uses 書く where English might say:

• fill out
• fill in
• complete

So with 申請書 (application form), 書く can naturally mean write on the form / fill out the form.

届出人 is a formal noun meaning the person who submits or files a notice, report, or registration.

It is made from:

• 届出 = filing, notification, submission of a notice
• 人 = person

So it is not just any random person. It is a role word often used in official or administrative contexts.

Depending on context, it might be translated as:

• the filer
• the declarant
• the person submitting the notice

申請書 means application form or written application.

It is made from:

• 申請 = application, request, petition
• 書 = document, written form

So it refers to the form/document itself, not just the act of applying.

Japanese does not normally use articles like English a, an, and the.

So 届出人 could mean:

• a filer
• the filer
• the applicant

And 申請書 could mean:

• an application form
• the application form

The exact meaning depends on context. Japanese often leaves this kind of information unstated unless it needs to be specific.

書く is the plain non-past form.

In Japanese, the non-past form can mean:

• present habitual: writes
• future: will write

So this sentence could mean:

• The filer writes the application form
• The filer will write the application form

The correct interpretation depends on context.

It is grammatically in the plain form because the verb is 書く, not 書きます.

However, the vocabulary itself is quite formal and administrative:

• 届出人
• 申請書

So the overall impression is:

• plain in verb form
• but formal in wording

This kind of sentence feels like something from a form, manual, explanation, or official document rather than everyday casual conversation.

Yes. Japanese often omits information that is understood from context.

For example, if it is already obvious who is writing, someone might just say:

申請書を書く。
= (I/they/he/she) write(s) the application form

Or if the form is already understood:

届出人が書く。
= The filer writes it

In full example sentences, Japanese often includes everything for clarity, but real conversation frequently leaves out subjects and objects.

Because Japanese is basically an SOV language:

• S = subject
• O = object
• V = verb

So a basic sentence often looks like:

subject + object + verb

That is why:

• 届出人 = subject
• 申請書 = object
• 書く = verb at the end

This is one of the biggest word-order differences from English, which is usually SVO:

The filer writes the application form.