Ona je tačno napisala moju adresu.

Yes. Serbian often does drop the subject pronoun when it is already clear from the verb or the context.

So instead of Ona je tačno napisala moju adresu, you could often just say:

Tačno je napisala moju adresu.

The pronoun ona is included when you want to:

• make the subject explicit,
• emphasize she,
• contrast her with someone else.

So ona here can sound a bit like she in English with mild emphasis.

Je is the 3rd person singular present form of the verb biti (to be), and here it helps form the past tense.

Serbian past tense is usually made with:

• a present form of biti
• plus the past participle

So:

• ona je napisala = she wrote / she has written

The participle agrees with the subject:

• napisao = masculine singular
• napisala = feminine singular
• napisalo = neuter singular
• napisali / napisale = plural

Because the subject is ona (she), we get napisala.

Both are possible, but they mean slightly different things because Serbian verbs often come in aspect pairs.

• pisati = to write (imperfective)
• napisati = to write down / to write completely (perfective)

So:

• pisala focuses more on the process or ongoing action.
• napisala focuses on the completed result.

In this sentence, napisala is natural because the idea is that she successfully wrote the address down.

In this sentence, tačno most naturally means correctly / accurately.

So Ona je tačno napisala moju adresu means she wrote your address without mistakes.

Depending on context, tačno can also mean:

• exactly
• precisely
• accurately
• correctly

Here, because it modifies napisala moju adresu, English usually prefers correctly or accurately.

Here tačno is an adverb. It describes how she wrote the address.

• tačan = accurate, correct, exact (adjective)
• tačno = accurately, correctly, exactly (adverb)

Compare:

• To je tačna adresa. = That is the correct address.
• Ona je tačno napisala adresu. = She wrote the address correctly.

Because moju adresu is the direct object of the verb napisala.

She wrote what?

• moju adresu = my address

In Serbian, direct objects often go in the accusative case.

So:

• moja adresa = nominative, my address
• moju adresu = accusative, my address as the object

Both words change because:

• moja becomes moju
• adresa becomes adresu

In Serbian, adjectives and possessive words usually agree with the noun they describe in:

• gender
• number
• case

Here:

• adresa is feminine singular
• it is in the accusative
• so the possessive moja must also be feminine singular accusative

That gives:

• moja adresa (nominative)
• moju adresu (accusative)

This kind of agreement is a very important part of Serbian grammar.

Yes. Serbian word order is more flexible than English word order.

The neutral order here is:

Ona je tačno napisala moju adresu.

But depending on emphasis, you might also hear:

• Tačno je napisala moju adresu.
• Moju adresu je tačno napisala.
• Ona je moju adresu tačno napisala.

The meaning stays basically the same, but the focus changes.

One important thing: je is a clitic, so it usually goes in the second position of the clause.

Serbian has a group of short unstressed words called clitics, and they usually appear near the beginning of the sentence, often in second position.

In your sentence:

• Ona = first element
• je = second-position clitic

So:

• Ona je tačno napisala moju adresu.

If another element comes first, je usually follows that first element:

• Tačno je napisala moju adresu.
• Moju adresu je tačno napisala.

This does not mean it has to be the second word literally in every possible analysis, but for learners, second position is a very useful rule of thumb.

Yes. The Serbian past tense here can often correspond to either:

• she wrote
• she has written

Which English translation sounds best depends on context.

Serbian does not always make the same distinction English does between:

• a simple past event
• a present-relevant completed action

So ona je napisala can work for both, depending on the situation.

Yes, adresa is a normal Serbian word meaning address. It is a feminine noun.

Its forms include:

• adresa = nominative
• adrese = genitive / sometimes nominative plural depending on context
• adresu = accusative
• adresi = dative/locative
• adresom = instrumental

Many Serbian words are international or borrowed, so it is normal to find familiar-looking vocabulary.

Sometimes, yes, but the nuance changes.

• tačno = correctly, exactly, accurately
• precizno = precisely, with precision

In this sentence, tačno is more natural if you mean the address was written without error.

Precizno would sound more like the writing was done in a precise, careful manner, which is a slightly different idea.

So for most learners, tačno is the best choice here.

Then the past participle would change to match a masculine subject:

• Ona je tačno napisala moju adresu. = She wrote my address correctly.
• On je tačno napisao moju adresu. = He wrote my address correctly.

The important change is:

• napisala → feminine
• napisao → masculine

The auxiliary je stays the same because it is still 3rd person singular.