O pedido chegou hoje.

In this sentence, pedido most naturally means order, especially in a shopping or delivery context.

A useful nuance:

• pedido = the order you placed
• encomenda = the parcel/package being delivered

So O pedido chegou hoje is perfectly understandable as The order arrived today, though in some contexts a Portuguese speaker might also say A encomenda chegou hoje if they are thinking of the physical package.

Also, pedido can mean request in other contexts, but that would not usually fit well with chegou here.

Because Portuguese normally uses the definite article much more often than English.

So:

• O pedido chegou hoje. = The order arrived today.

If you say just Pedido chegou hoje, it sounds incomplete in normal everyday Portuguese, unless it is a headline, a note, or very telegraphic speech.

Yes, pedido is a masculine singular noun here, which is why it takes o.

You can see that in:

• o pedido = the order

A few related forms:

• os pedidos = the orders
• um pedido = an order

Many nouns ending in -o are masculine, and pedido is one of them, though that pattern is not a perfect rule for every noun in Portuguese.

Chegou is the 3rd person singular preterite of the verb chegar.

• chegar = to arrive
• chegou = arrived

It matches o pedido, which is singular:

• O pedido chegou = The order arrived

If the subject were plural, the verb would change:

• Os pedidos chegaram hoje. = The orders arrived today.

This is a very important point for European Portuguese.

In English, you often say:

• The order has arrived today.

In European Portuguese, for a single completed event, the normal choice is usually the simple past:

• O pedido chegou hoje.

That is true even with hoje (today).

This is because the Portuguese form that looks like the English present perfect:

• tem chegado

usually does not mean the same thing. In European Portuguese, it often suggests something repeated or happening over a period of time, not one single completed arrival.

So for one arrival today, chegou is the natural form.

It is the subject.

The structure is:

• O pedido = subject
• chegou = verb
• hoje = time expression

So literally:

• The order arrived today

The verb chegar is not taking a direct object here. It works like to arrive in English.

Yes, hoje can move around. Portuguese word order is fairly flexible with time expressions.

These are all possible:

• O pedido chegou hoje. = neutral, very natural
• Hoje o pedido chegou. = emphasizes today
• Hoje chegou o pedido. = also natural, a bit more focused on the event happening today

The version with hoje at the end is a very normal default sentence order.

A rough European Portuguese pronunciation is:

u puh-DEE-doo shuh-GOH OH-zhuh

More carefully:

• o often sounds like u when unstressed
• ch in chegou sounds like English sh
• j in hoje sounds like the s in measure
• unstressed vowels are often reduced in European Portuguese

A more technical IPA version is approximately: [u pɨˈðiðu ʃɨˈɣo ˈoʒɨ]

The main thing for a learner is that European Portuguese often reduces unstressed vowels much more than Brazilian Portuguese.

Yes, absolutely.

There is a small difference in focus:

• O pedido chegou hoje = the order arrived today
• A encomenda chegou hoje = the package/parcél arrived today

In online shopping, both can appear, but:

• pedido focuses more on the order you made
• encomenda focuses more on the item/package in delivery

So if you are specifically talking about the delivery reaching your house, encomenda can sound especially natural.

You need to change both the article, the noun, and the verb:

• O pedido chegou hoje. = The order arrived today.
• Os pedidos chegaram hoje. = The orders arrived today.

So:

• o → os
• pedido → pedidos
• chegou → chegaram

This is a good example of subject-verb agreement in Portuguese.