Ostavite prijavu u kancelariji.

Ostavite is the imperative form of the verb ostaviti, meaning leave.

More specifically, it is:

• 2nd person plural imperative
• used for you all
• or for one person formally/politely (Vi)

So it can mean:

• Leave ... when speaking to several people
• Please leave ... when speaking politely to one person

The ending -te marks the plural/formal imperative.

Compare:

• ostavi = leave! (said to one person informally)
• ostavite = leave! (said to several people, or to one person politely)

This is a very common pattern in Serbian imperatives.

It is not stated explicitly, because Serbian usually does not need subject pronouns when the verb ending already shows who is being addressed.

Here, ostavite already tells you that the subject is:

• you all, or
• you in a formal sense

So Serbian often leaves out vi unless it is needed for emphasis.

Because prijavu is in the accusative singular.

The base form is:

• prijava = application / registration / report

In this sentence, it is the direct object of ostavite, so Serbian uses the accusative case.

For many feminine nouns ending in -a, the accusative singular changes:

• -a → -u

So:

• prijava → prijavu

Kancelariji is in the locative singular.

The noun is:

• kancelarija = office

After the preposition u, Serbian often uses:

• locative for location: in / at
• accusative for movement toward something: into

Here the meaning is in the office / at the office, so Serbian uses the locative:

• u kancelariji

This is a very important Serbian pattern:

• u + locative = in / at a place
• u + accusative = into / to a place

So:

• u kancelariji = in the office
• u kancelariju = into the office

In your sentence, the focus is on where the application should be left, so u kancelariji is used.

This is about aspect, which is very important in Serbian verbs.

• ostaviti = perfective
• ostavljati = imperfective

So:

• ostavite usually means leave it / do this action once, as a completed action
• ostavljajte would suggest repeated, habitual, or sometimes more ongoing action

In an instruction like this, Serbian usually prefers the perfective imperative:

• Ostavite prijavu u kancelariji.

That sounds natural for a single completed action.

No. In Serbian, the imperative is often perfectly normal in:

• instructions
• notices
• office directions
• public signs

So Ostavite prijavu u kancelariji. can sound like a standard instruction, not necessarily rude.

If someone wanted to sound softer in conversation, they might say:

• Molim vas, ostavite prijavu u kancelariji.

That adds please and makes the tone more polite.

Yes. Serbian word order is fairly flexible.

The neutral version is:

• Ostavite prijavu u kancelariji.

But you could also say:

• Prijavu ostavite u kancelariji.
• U kancelariji ostavite prijavu.

These versions change the emphasis, not the basic meaning.

For example:

• Prijavu ostavite u kancelariji. emphasizes the application
• U kancelariji ostavite prijavu. emphasizes the office

Because Serbian does not have articles like English the and a/an.

So prijavu can mean:

• the application
• an application

Which one is meant depends on the context.

That is completely normal in Serbian. The language leaves this kind of information to context instead of using articles.

The dictionary forms are:

• ostaviti = to leave
• prijava = application / registration / report
• kancelarija = office

In the sentence, they appear as:

• ostavite = imperative form of ostaviti
• prijavu = accusative singular of prijava
• kancelariji = locative singular of kancelarija

This is a useful way to study Serbian sentences: identify the dictionary form first, then the case or verb form used in context.