Mas di loket bilang bahwa saya harus fotokopi kartu identitas dulu.

Mas is a polite way to refer to a young man, especially in Java and in Indonesian influenced by Javanese usage. In this sentence, it means something like the young man / the male clerk at the counter.

It does not literally mean the speaker’s older brother here, even though that is one original meaning of mas in Javanese. In everyday Indonesian, it is often used as a respectful form of address for a man.

Here, di is a preposition, meaning at / in / on depending on context. So di loket means at the counter / at the service window.

A useful clue is spelling: the preposition di is written separately from the noun, as in di loket. The passive prefix di- is written attached to the verb, as in difotokopi or ditulis.

In Indonesian, it is very normal to put a location phrase after a noun to identify which person you mean. So Mas di loket literally looks like the young man at the counter.

The phrase di loket describes Mas, not the verb bilang. It helps specify which Mas the speaker is talking about.

Loket usually means a service window, ticket window, counter, or booth where someone handles documents, tickets, payments, and similar things.

So in this sentence, it refers to the place where the clerk was sitting or working. It is a very common word in offices, stations, hospitals, banks, and government buildings.

Bilang is common and natural in everyday spoken Indonesian. It means to say / to tell.

Compared with mengatakan or berkata, bilang sounds more conversational. So this sentence sounds quite natural in speech. In a more formal written style, you might see mengatakan bahwa... instead.

Bahwa means that when introducing a reported statement. It connects bilang with the content of what was said.

Yes, it can often be omitted in everyday Indonesian, especially after bilang. So Mas di loket bilang saya harus fotokopi kartu identitas dulu is also very natural. Keeping bahwa makes the structure a little clearer and slightly more formal.

In everyday Indonesian, many verbs—especially common borrowed words—are often used in a bare form without the meN- prefix. So fotokopi can function as a verb meaning to photocopy.

In more careful or formal language, memfotokopi is also possible. Both are understandable, but harus fotokopi sounds very natural in conversation.

Yes. Fotokopi can mean a photocopy as a thing, or to photocopy as an action, depending on context.

In this sentence, it is a verb because it follows harus and describes what the speaker needs to do. Indonesian often allows this kind of flexible word use.

Kartu identitas means an identity card / identification card. It is a general expression, not necessarily one specific type of ID.

Depending on the situation, it could refer to a national ID card, student ID, work ID, or another official identification card. If the speaker meant a specific one, Indonesian might use a more specific term such as KTP.

Indonesian does not use articles like English the or an. So kartu identitas can mean an ID card, the ID card, or just ID card depending on context.

Possession is also only added if needed. If the speaker wanted to say my ID card explicitly, they could say kartu identitas saya.

Harus expresses necessity or obligation, like must / have to / need to in English. It is followed directly by a verb or verb-like expression.

So saya harus fotokopi... means the speaker is required to do that action. Indonesian does not need an extra word like English to after must.

That is a very common source of confusion. In this sentence, dulu means first or before continuing, not a long time ago.

So fotokopi kartu identitas dulu means something like photocopy the ID card first. It suggests this step must happen before the next step in the process.

Sometimes, yes, especially in casual speech if the meaning is already obvious. For example, people may say Mas di loket bilang harus fotokopi kartu identitas dulu.

However, keeping saya is clearer because it explicitly shows that I am the one who has to do the photocopying. Without it, the sentence can still be understood, but it is slightly less explicit.

Several alternatives are natural:

• Mas di loket bilang saya harus fotokopi kartu identitas dulu.
  Very natural in speech.

• Mas di loket bilang bahwa saya harus memfotokopi kartu identitas dulu.
  Slightly more formal because of bahwa and memfotokopi.

• Petugas di loket mengatakan bahwa saya harus memfotokopi kartu identitas terlebih dahulu.
  Much more formal and more typical of careful written Indonesian.

So the original sentence sounds like normal everyday spoken Indonesian.