A lakcím a kérelmen van.

Lakcím means home address or residential address.

It is a compound word:

• lak- relates to living/residing (compare lakni = to live somewhere)
• cím = address

So lakcím is not just any kind of address in every context; it often means the address where a person officially lives.

Because Hungarian uses the definite article a / az much like English the.

Here:

• A lakcím = the address
• a kérelmen = on the application / on the form / on the request

Hungarian repeats the article with each definite noun phrase, just as English does:

• the address
• the application

So having a twice is completely normal.

Because kérelmen has a case ending added to it.

The base noun is:

• kérelem = application, request

Here it becomes:

• kérelmen = on the application/request

The ending -n / -on / -en / -ön often means on.

So:

• asztal → asztalon = on the table
• papír → papíron = on the paper
• kérelem → kérelmen = on the application

The word changes slightly when the ending is attached: kérelem → kérelm- + -en.

It is in the superessive case.

The superessive usually means on a surface, or sometimes on/in certain set expressions.

In this sentence:

• a kérelmen = on the application

This is one of the basic Hungarian location cases:

• -ban / -ben = in
• -on / -en / -ön / -n = on
• -nál / -nél = at/by

So the sentence uses a location phrase: a kérelmen.

Because this sentence expresses location: something is somewhere.

Hungarian often leaves out van in the present tense when saying that something is something:

• Ez egy kérelem. = This is an application.
• A cím fontos. = The address is important.

But when you say that something is somewhere, Hungarian normally uses van:

• A lakcím a kérelmen van. = The address is on the application.
• A könyv az asztalon van. = The book is on the table.

So here van is necessary because the sentence is about where the address is.

This is a natural, neutral Hungarian word order:

• A lakcím = topic, what we are talking about
• a kérelmen = location
• van = is

So the structure is roughly:

[topic] + [location] + van

Hungarian word order is flexible, but it often reflects focus or emphasis.

This version sounds like:

• As for the address, it is on the application.

Yes, but it means something slightly different in emphasis.

• A lakcím a kérelmen van. = neutral; the address is on the application.
• A lakcím van a kérelmen. = puts more focus on lakcím; it can sound like It’s the address that is on the application.

So both can be grammatical, but the original sentence is the more neutral version if you are simply stating location.

Not always.

Kérelem can mean things like:

• request
• application
• petition

The best English translation depends on context.

So a kérelmen could mean:

• on the application
• on the request form
• on the petition

If your learning material gives application, that is probably the intended meaning in this context.

Because the definite article depends on the sound that follows:

• a before a consonant
• az before a vowel

Since kérelmen begins with k, a consonant, Hungarian uses:

• a kérelmen

Compare:

• a lakcím
• a kérelem
• az asztalon (because asztalon begins with a vowel sound)

Not in this sentence, because lakcím is the subject.

• A lakcím = the address

It is in its basic dictionary form here.

The word that gets the location ending is kérelem, because that is the place where the address is located:

• kérelmen = on the application

So the sentence is structured like this:

• A lakcím = subject
• a kérelmen = location phrase
• van = verb

It most naturally means that the address is written on the application/form.

Hungarian uses the same location structure for that:

• A név a lapon van. = The name is on the sheet.
• A cím a borítékon van. = The address is on the envelope.

So even though it uses a literal location expression (on), it is very natural for information that appears on a document.