डाकघर पार्सल घर पहुँचाएगा।

A simple breakdown is:

• डाकघर = post office
• पार्सल = parcel
• घर = home / house
• पहुँचाएगा = will deliver / will cause to reach

So the structure is basically:

• subject: डाकघर
• object: पार्सल
• destination: घर
• verb: पहुँचाएगा

The literal sense is something like The post office will make the parcel reach home, which in natural English becomes The post office will deliver the parcel home.

Hindi usually prefers Subject + Object + Verb order, and other information such as place or destination typically comes before the verb too.

So:

• डाकघर = subject
• पार्सल = object
• घर = destination
• पहुँचाएगा = verb

That gives:

डाकघर पार्सल घर पहुँचाएगा।

In English, the verb usually comes earlier:
The post office will deliver the parcel home.

In Hindi, the verb normally comes at the end.

Hindi does not always mark the direct object with को.

Here, पार्सल is a direct object, but को is often omitted when the object is:

• inanimate
• indefinite or generic
• not being specially emphasized

Since पार्सल is an inanimate thing, पार्सल without को sounds natural.

You may sometimes hear पार्सल को in other contexts, especially if the object is specific or emphasized, but in this sentence पार्सल without को is perfectly normal.

In Hindi, some destination words can appear without an extra postposition, especially common place words like घर.

So घर पहुँचाना means to deliver/reach to the home in a natural, idiomatic way.

This is similar to how English can say:

• go home
• not usually go to home

Hindi often treats घर in a special, very natural way.

You could also hear other versions in different contexts:

• घर तक पहुँचाएगा = will deliver up to the house/home
• घर पर पहुँचाएगा = will deliver at the house/home

But plain घर पहुँचाएगा is very natural.

पहुँचाएगा is the future masculine singular form of पहुँचाना, which means:

• to deliver
• to bring/send something to a destination
• literally, to cause something to reach

It is related to पहुँचना = to reach / arrive.

So:

• पार्सल घर पहुँचेगा = The parcel will reach home
• डाकघर पार्सल घर पहुँचाएगा = The post office will deliver the parcel home / will cause the parcel to reach home

That extra causative idea is important.

Because the sentence has an agent doing the action to something else.

Compare:

• पार्सल घर पहुँचेगा।
  = The parcel will reach home.
  Here, the parcel itself is the grammatical subject.

• डाकघर पार्सल घर पहुँचाएगा।
  = The post office will deliver the parcel home.
  Here, the post office causes the parcel to reach home.

So:

• पहुँचना = to reach
• पहुँचाना = to cause to reach / deliver

And पहुँचाएगा is the future form of that causative verb.

The ending -एगा here marks future tense and agrees with a masculine singular subject in this kind of sentence.

The base verb is पहुँचाना. In the future, it becomes forms like:

• पहुँचाएगा = he/it will deliver
• पहुँचाएगी = she/it will deliver
• पहुँचाएँगे = they / you-formal will deliver

In this sentence, the subject is डाकघर, which is grammatically treated as masculine singular, so पहुँचाएगा is the expected form.

In this sentence, डाकघर is the subject, so the verb agrees with डाकघर.

That is normal in non-perfective tenses like the future.

So:

• डाकघर = masculine singular subject
• therefore पहुँचाएगा = masculine singular verb form

If the subject changed, the verb would change too:

• डाक सेवा पार्सल घर पहुँचाएगी।
  Here डाक सेवा is feminine, so पहुँचाएगी.

• डाकघर वाले पार्सल घर पहुँचाएँगे।
  Masculine plural, so पहुँचाएँगे.

Because ने is not used in all tenses.

In Hindi, ने is mainly used with many perfective transitive clauses, not with the simple future like this.

So:

• डाकघर पार्सल घर पहुँचाएगा।
  future → no ने

But compare a perfective sentence:

• डाकघर ने पार्सल घर पहुँचाया।
  = The post office delivered the parcel home.

That is why ने is absent here.

In literal dictionary terms, डाकघर means post office. But in a sentence like this, it usually refers to the institution or service, not just the physical building.

So in English, the idea is closer to:

• the post office
• the postal service

rather than the building itself will do something.

This kind of shorthand is very common in both Hindi and English.

Yes. Hindi often allows several natural variations depending on style and emphasis. For example:

• डाकघर पार्सल घर पहुँचाएगा।
• डाकघर पार्सल घर तक पहुँचाएगा।
• डाकघर पार्सल आपके घर पहुँचाएगा।
• डाकिया पार्सल घर पहुँचाएगा।

These all relate to the same basic idea, but with slightly different nuance:

• घर = home
• घर तक = up to the home
• आपके घर = to your home
• डाकिया = postman / mail carrier instead of post office

So the original sentence is natural, but not the only possible way to express the idea.