Az önkéntes itt van.

Hungarian has two forms of the definite article:

• a before a consonant sound
• az before a vowel sound

Since önkéntes begins with ö, which is a vowel, you use az:

• az önkéntes = the volunteer

Compare:

• a tanár = the teacher
• az orvos = the doctor

At the start of the sentence it is capitalized: Az.

Önkéntes means volunteer.

It can be used as:

• a noun: an/the volunteer
• sometimes also an adjective in other contexts: voluntary

In this sentence, it is clearly a noun:

• Az önkéntes = the volunteer

Hungarian often does not use subject pronouns unless they are needed for emphasis or contrast.

In this sentence, the subject is already named:

• Az önkéntes = the volunteer

So there is no need to add anything like he or she. Hungarian normally avoids repeating information that is already clear.

Van is the 3rd person singular form of lenni, the verb to be.

In Hungarian, present-tense to be is often left out in sentences like:

• A tanár fáradt. = The teacher is tired.
• Az önkéntes orvos. = The volunteer is a doctor.

But when you are talking about location or existence, van is usually kept:

• Az önkéntes itt van. = The volunteer is here.
• A könyv az asztalon van. = The book is on the table.

So van appears because the sentence is about where someone is.

Itt means here.

It is an adverb of place, not a noun with a case ending.

Some useful related words are:

• itt = here
• ott = there
• ide = to here
• oda = to there

So:

• itt van = is here

Itt van is the most natural neutral order for is here in this sentence.

• Az önkéntes itt van. = The volunteer is here.

If you change the word order, the emphasis can change. For example:

• Az önkéntes van itt. can sound like It is the volunteer who is here.
• Van itt... often starts a different kind of sentence, more like There is ... here in some contexts.

Hungarian word order is flexible, but it is strongly connected to focus and emphasis, not just grammar.

Yes, in many situations itt van can be understood as is here or is present.

Its basic meaning is physical presence:

• The volunteer is here.

But depending on context, English might translate it as:

• The volunteer is here
• The volunteer is present
• The volunteer has arrived / is around

The most direct translation is still The volunteer is here.

You would use the indefinite article egy:

• Egy önkéntes itt van. = A volunteer is here.

So:

• az önkéntes = the volunteer
• egy önkéntes = a volunteer

This is an important contrast in Hungarian.

A helpful rough guide is:

• ön-kayn-tesh

A few key points:

• Hungarian stress is almost always on the first syllable: ÖNkéntes
• ö is like the vowel in German schön or French peu, if you know those
• é is a long vowel, somewhat like ay in say, but purer
• s in Hungarian is pronounced like English sh
• sz would be English s, but there is no sz here

So önkéntes sounds roughly like ÖN-kayn-tesh.

Because Hungarian uses van for is in location sentences.

• itt = here
• van = is

So:

• itt van = is here

English puts the verb before here: is here
Hungarian often puts the location word before the verb: itt van

That is just the normal Hungarian pattern.

Yes, but it does not sound the same as the neutral sentence.

• Az önkéntes itt van. = neutral: The volunteer is here.
• Az önkéntes van itt. = emphasis on the volunteer: It is the volunteer who is here.

So the second version is possible, but it usually answers a contrastive question such as:

• Ki van itt? = Who is here?
• Az önkéntes van itt. = The volunteer is here.

Yes, very common.

You will see the same structure with many subjects:

• Péter itt van. = Péter is here.
• A tanár itt van. = The teacher is here.
• Anyu itt van. = Mom is here.

This makes itt van a useful chunk to learn early. It is one of the standard ways Hungarian expresses someone’s presence or location.