Potvrda o prijavi stigla je danas.

Potvrda is in the nominative singular because it is the subject of the sentence — the thing that arrived.

The dictionary form is potvrda and it is a feminine noun. In this sentence, it means confirmation.

Because the preposition o normally requires the locative case when it means about / concerning.

The noun is prijava, and its locative singular is prijavi.

So:

• prijava = nominative
• o prijavi = about the application/registration

It is locative singular.

This is very common after the preposition o:

• o školi = about the school
• o knjizi = about the book
• o prijavi = about the application/registration

For feminine nouns ending in -a, the locative singular is often -i.

Stigla je is the past tense.

It is made of two parts:

• stigla = the l-participle
• je = the auxiliary verb to be

The infinitive is stići, meaning to arrive.

So stigla je means arrived or has arrived, depending on how you would naturally say it in English.

Because stigla agrees with potvrda, which is feminine singular.

In Croatian past tense, the participle agrees with the subject in gender and number:

• stigao = masculine singular
• stigla = feminine singular
• stiglo = neuter singular

Since potvrda is feminine, the sentence uses stigla.

Croatian word order is more flexible than English word order.

The sentence Potvrda o prijavi stigla je danas is natural and correct. You may also hear other orders, such as:

• Potvrda o prijavi je stigla danas
• Danas je stigla potvrda o prijavi

These versions are all possible, but they sound slightly different in rhythm or emphasis.

A useful thing to remember is that je is a clitic, so it does not normally stand at the very beginning of the sentence by itself.

Because Croatian has no articles.

So potvrda can mean:

• a confirmation
• the confirmation

The context tells you which meaning is intended.

That is why Croatian learners often have to get used to reading nouns without any equivalent of a/an/the.

Yes, literally o prijavi is something like about the application/registration.

But Croatian and English do not always build noun phrases in the same way. In administrative or formal language, Croatian often uses structures that are most naturally translated into English with of:

• potvrda o prijavi → confirmation of registration/application

So the Croatian wording is normal, even if the most natural English translation is not completely literal.

Yes. Prijava can mean different things depending on context, for example:

• application
• registration
• sign-up
• report

So potvrda o prijavi could mean things like:

• application confirmation
• confirmation of registration
• confirmation of submission

The exact English wording depends on the situation.

Yes. Croatian allows adverbs like danas to move around more freely than English does.

For example, all of these are possible:

• Potvrda o prijavi stigla je danas.
• Danas je stigla potvrda o prijavi.
• Potvrda o prijavi danas je stigla.

The meaning stays basically the same, but the emphasis shifts slightly. The original sentence sounds quite neutral and natural.