Ako joj ga večeras pošalješ, odgovor će ti dati već sutra ujutro.

In Croatian, after ako for a real future condition, you normally use the present, not a future form.

So:

• Ako joj ga večeras pošalješ = If you send it to her this evening
• not usually Ako ćeš joj ga poslati...

Here pošalješ is a present form, but because the verb is perfective, it refers to a single completed action in the future. This is very common in Croatian.

This is a matter of aspect.

• pošalješ comes from poslati and is perfective
• šalješ comes from slati and is imperfective

Very roughly:

• pošalješ = send once / send off / complete the sending
• šalješ = are sending / send habitually / send over a period of time

In this sentence, the perfective verb fits because the meaning is: first you complete one action of sending, then she gives you an answer.

They are all short unstressed pronouns called clitics.

• joj = to her (dative)
• ga = him or it (accusative/genitive clitic; here it means it)
• ti = to you (dative)

So the sentence structure is basically:

• Ako joj ga večeras pošalješ = If you send it to her this evening
• odgovor će ti dati = she will give you an answer

Because Croatian clitics have a fairly fixed order.

When both appear together here, the dative pronoun normally comes before the accusative pronoun:

• joj ga = to her it
• not ga joj

So even though English says send it to her, Croatian uses the clitic order to her it.

Ga is the short form for a masculine or neuter singular object, depending on the noun it stands for.

So it can mean:

• him
• it

For example:

• dokument → ga
• pismo → ga

In your sentence, it is understood as it, because the meaning has already been established in context.

Yes. Odgovor is the direct object of dati.

Literally, that part is:

• odgovor = an answer
• će dati = will give
• ti = to you

So: will give you an answer

Croatian word order is flexible, and here odgovor is placed first in the clause. That helps the clitics će ti sit in their normal second position, and it also gives a little emphasis to answer.

Standard Croatian forms the future with the clitic forms of htjeti plus the infinitive.

Here you have:

• će dati = will give

Because će is a clitic, it normally comes after the first stressed word or phrase in the clause. In this sentence, that is odgovor, so you get:

• Odgovor će ti dati

If the infinitive itself comes before će, standard Croatian usually drops the final -i:

• Dat će ti odgovor

So dati će is generally not the standard written form.

It is accusative singular, but for many masculine inanimate nouns, the accusative singular looks exactly the same as the nominative singular.

So:

• nominative: odgovor
• accusative: odgovor

You know it is accusative here because it is the direct object of dati.

Here već means something like:

• already
• as early as
• by then already

So:

• već sutra ujutro = already tomorrow morning / as early as tomorrow morning

It adds the nuance that the answer will come surprisingly soon or sooner than expected.

Because Croatian often uses time adverbs directly, without needing a preposition.

• večeras = this evening / tonight
• sutra = tomorrow
• ujutro = in the morning

So:

• sutra ujutro = tomorrow morning

This is perfectly normal Croatian.

Croatian often leaves subject pronouns out when they are clear from context. This is called pro-drop.

So instead of saying:

• Ona će ti dati odgovor

Croatian can simply say:

• Odgovor će ti dati

The subject she is understood from the situation and the meaning already provided.

Yes, to some extent. Croatian word order is flexible, but clitics are much less flexible.

For example, these are possible with different emphasis:

• Ako joj ga pošalješ večeras, odgovor će ti dati već sutra ujutro.
• Ako joj ga večeras pošalješ, dat će ti odgovor već sutra ujutro.
• Ona će ti dati odgovor već sutra ujutro.

But you cannot freely scramble the clitics:

• joj ga is fine
• ga joj is not the normal order here

So the main thing is:

• content words can move around more
• clitics follow stricter rules

Yes. A very natural alternative would be:

• Ako joj ga večeras pošalješ, odgovorit će ti već sutra ujutro.

That means essentially the same thing: If you send it to her this evening, she’ll answer you as early as tomorrow morning.

The version with dati odgovor literally means give an answer, which is also perfectly normal Croatian. It can sound a little more explicit or slightly more formal depending on context.