Kartu identitas disimpan di dompet kecil supaya tidak hilang.

Disimpan is the passive form of simpan (to store / keep).

• menyimpan = to store / keep something (active)
• disimpan = is stored / is kept (passive)

So:

• Saya menyimpan kartu identitas. = I store / keep the ID card.
• Kartu identitas disimpan... = The ID card is kept / stored...

In this sentence, the focus is on kartu identitas, not on who is doing the action.

This is a very common Indonesian question because they look similar but are different things.

• di- attached to a verb = a passive prefix
  • disimpan = is kept / is stored
• di written separately = a preposition meaning in / at / on
  • di dompet kecil = in a small wallet

So:

• disimpan → one word, because di- is part of the verb
• di dompet → two words, because di means location

In Indonesian, adjectives usually come after the noun.

So:

• dompet kecil = small wallet
• rumah besar = big house
• mobil baru = new car

This is different from English, where adjectives usually come before the noun.

Supaya means so that or in order that.

It introduces the purpose of the action:

• Kartu identitas disimpan di dompet kecil = The ID card is kept in a small wallet
• supaya tidak hilang = so that it does not get lost

So the second part explains why the card is kept there.

Hilang means lost or to be lost / disappear.

In this sentence, the idea is:

• supaya tidak hilang = so that it doesn’t get lost

You would not use kehilangan here, because kehilangan usually means to lose something.

Compare:

• Saya kehilangan dompet. = I lost my wallet.
• Dompet saya hilang. = My wallet is lost / disappeared.

Here, the ID card is the thing that might become lost, so hilang is the natural choice.

Yes. The implied subject is kartu identitas.

The sentence literally works like this:

• Kartu identitas disimpan di dompet kecil = The ID card is kept in a small wallet
• supaya [kartu identitas itu] tidak hilang = so that [the ID card] does not get lost

Indonesian often leaves out words that are already understood from context.

Yes. Supaya and agar are often interchangeable and both can mean so that.

For example:

• Kartu identitas disimpan di dompet kecil supaya tidak hilang.
• Kartu identitas disimpan di dompet kecil agar tidak hilang.

Both are natural.
Very generally:

• supaya can sound a bit more common in everyday speech
• agar can sound slightly more formal or careful

But in many situations, either one is fine.

Because Indonesian often uses the passive when the doer is unknown, unimportant, or obvious from context.

So Kartu identitas disimpan... means:

• The ID card is kept...
• The ID card is stored...

It does not tell us exactly who does it. That is normal and natural in Indonesian.

If you wanted to mention the doer, you could add it:

• Kartu identitas disimpan oleh pemiliknya di dompet kecil. = The ID card is kept by its owner in a small wallet.

But this is less necessary unless the doer matters.

By itself, kartu identitas can mean:

• an ID card
• the ID card
• sometimes ID cards in a general sense, depending on context

Indonesian does not use articles like a, an, and the the way English does, so context decides the most natural translation.

In this sentence, English would usually say The ID card or An ID card, depending on the situation.

Indonesian does not have to mark plural the way English does.

So kartu identitas could mean:

• ID card
• ID cards

If the speaker wants to make plurality very clear, they can use reduplication:

• kartu-kartu identitas = ID cards

But here, the sentence most naturally sounds singular from context.

Yes. Dompet usually means wallet, but depending on context it can also refer to a small purse, coin purse, or similar small holder.

So dompet kecil is literally small wallet, but the exact English translation may vary depending on what kind of object the speaker has in mind.

The given word order is natural and clear:

• Kartu identitas disimpan di dompet kecil supaya tidak hilang.

It follows a common pattern:

• topic/subject
  • passive verb
    • location
      • purpose

You could change the order a little for emphasis, but the original is very standard.

For example:

• Supaya tidak hilang, kartu identitas disimpan di dompet kecil.

This puts more emphasis on the purpose first: So that it doesn’t get lost, the ID card is kept in a small wallet.