يبلغ صاحب المحفظة عنها.

Because Arabic normally leaves out short vowels and the shadda in ordinary writing.

So يبلغ can represent more than one verb form. In this sentence, the context tells you it is يُبَلِّغُ from بلّغ, with the meaning of report / inform / notify. The clue is the phrase عنها, since this reporting meaning commonly goes with عن.

If it were يَبْلُغُ, it would mean he reaches / attains, which does not fit this sentence well.

Because verb–subject–object/complement order is very common in Modern Standard Arabic.

So:

يبلغ صاحبُ المحفظةِ عنها

literally follows the pattern:

reports the owner of the wallet about it

That sounds odd in English, but it is a normal Arabic sentence order.

You could also say:

صاحبُ المحفظةِ يبلغ عنها

That is also grammatical, but starting with the verb is a very standard neutral pattern in MSA.

It is an iḍāfa construction, often called the genitive/possessive construction.

Literally, Arabic says:

owner the-wallet

but the meaning is:

the owner of the wallet

Arabic usually does not use a separate word for of in this kind of phrase. Instead, it puts two nouns together in an iḍāfa.

So:

• صاحب = owner / holder
• المحفظة = the wallet

Together:

صاحب المحفظة = the owner of the wallet

Because in an iḍāfa, the first noun normally does not take الـ.

So even though English says the owner, Arabic says:

صاحب المحفظة

not:

الصاحب المحفظة

The whole phrase becomes definite because the second noun is definite:

• المحفظة = the wallet

That makes the whole iḍāfa definite:

• صاحب المحفظة = the owner of the wallet

In an iḍāfa, the second noun is in the genitive case.

So in fully inflected Arabic, you would have:

• صاحبُ = nominative, because it is the subject of the verb
• المحفظةِ = genitive, because it is the second term of the iḍāfa

So a fully vowelled version would be:

يُبَلِّغُ صاحبُ المحفظةِ عنها

In everyday reading and pronunciation, those final case vowels are often not shown or not pronounced clearly, but the grammar is still there.

عنها is made of:

• عن = about / concerning
• ها = her / it (feminine singular)

So عنها literally means:

about her or about it

In this sentence, ها refers back to المحفظة, which is a feminine noun in Arabic. So in natural English, it is usually translated as it, not her.

Because the sentence is using a construction where the thing being reported is introduced with عن.

So Arabic says something like:

يبلغ عنها
= he reports it / reports about it

If you attached ها directly to the verb, as in يبلغها, that would suggest a different structure and likely a different meaning, closer to he informs her/it rather than he reports it.

So عن is important here.

Grammatically, yes. In Arabic, pronouns follow grammatical gender, not natural gender alone.

Since محفظة is a feminine singular noun, Arabic refers back to it with ها.

So:

• Arabic grammar: feminine singular pronoun
• Natural English translation: usually it

This is very common with non-human nouns in Arabic.

Yes. صاحب has a broader range of meanings, such as:

• owner
• possessor
• companion
• person associated with something

In this sentence, owner / holder is the natural meaning because it is followed by المحفظة.

So صاحب المحفظة is best understood here as the owner of the wallet.

Not as a separate word. Arabic often expresses of through the iḍāfa construction rather than with an independent preposition.

So instead of saying:

owner of the wallet

with a separate word for of, Arabic simply says:

صاحب المحفظة

This is one of the most basic and common structures in Arabic, so it is worth getting comfortable with early.

You can break it down like this:

• يبلغ = the verb, reports / informs
• صاحبُ المحفظةِ = the subject, the owner of the wallet
• عنها = a prepositional phrase, about it

So the sentence structure is:

verb + subject + prepositional phrase

That makes it a very useful example of several common Arabic features at once:

• verb-first word order
• iḍāfa
• attached pronouns
• use of a preposition with a verb