В отделе кадров мне сказали, что заявление уже подписано и можно идти домой.

Because в отделе кадров means in the HR department, so it expresses location, not motion.

• в + prepositional case = in/at a place
• в + accusative case = into/to a place

Compare:

• Я в отделе кадров. = I am in the HR department.
• Я иду в отдел кадров. = I am going to the HR department.

Also, отдел кадров is a fixed expression meaning personnel department / HR department. The word кадров is genitive plural here and stays that way in this expression, while отделе changes because of the prepositional case after в.

Because мне means to me, and in Russian the person receiving the information is often put in the dative case.

So:

• мне = to me
• сказали = they said / told

Literally, this part is something like to me they said.

Russian uses this structure very naturally when reporting what someone told you.

This is a very common Russian pattern: a 3rd person plural verb with no explicit subject can mean they, people, or someone in a vague, unspecified way.

So мне сказали often means:

• I was told
• They told me
• Someone told me

It does not necessarily mean a specific group of people. It is just a natural way to leave the speaker unspecified.

Что introduces a subordinate clause, like that in English.

So:

• мне сказали = I was told / they told me
• что заявление уже подписано... = that the application has already been signed...

In everyday English, that is often omitted, but in Russian что is normally stated.

Подписано is a short passive participle from подписать.

It means:

• has been signed
• is signed

So заявление уже подписано means the application/document has already been signed.

This structure focuses on the result/state, not on who did the signing.

A rough breakdown:

• заявление = application / statement / form
• подписано = signed

Because заявление is neuter singular, the short passive participle is also neuter singular: подписано.

Compare:

• Документ подписан. = The document is signed.
• Заявление подписано. = The application is signed.
• Бумаги подписаны. = The papers are signed.

Because it agrees with заявление, and заявление is a neuter singular noun.

Russian short passive participles agree in gender and number with the noun they describe:

• masculine: подписан
• feminine: подписана
• neuter: подписано
• plural: подписаны

Since заявление ends in -ие and is neuter singular, the correct form is подписано.

Можно is an impersonal word meaning it is possible, it is allowed, or one may.

So можно идти домой means something like:

• it’s okay to go home
• you can go home
• one may go home

This sounds more natural here than я могу идти домой, which would focus more on my ability rather than permission or the situation allowing it.

So the sentence means that after the application was signed, it became acceptable/allowed for the speaker to leave.

Both can be possible in some contexts, but идти after можно often expresses the general action to go / to be on one’s way.

Here можно идти домой sounds like:

• you can go home now
• you’re free to head home

If you said можно пойти домой, it would put a bit more focus on the beginning of the action: you may set off/go.

In many everyday situations, both are understandable, but можно идти домой is very natural in this kind of office or procedural context.

Домой is a special adverb meaning homeward / to home / home.

Russian often uses special adverbs for movement toward a place:

• домой = home
• сюда = here
• туда = there

So:

• идти домой = to go home

Compare:

• дом = house/home as a noun
• к дому = toward the house / to the house

Домой is the normal word when someone is returning home.

Уже means already.

In заявление уже подписано, it shows that the signing is completed by now.

So it adds the idea:

• the application has already been signed
• the application is signed already

It often signals that something expected or necessary has now happened.

There is a comma before что because что introduces a subordinate clause:

• мне сказали, что... = they told me that...

There is no extra comma before и можно идти домой because и simply joins two parts inside that subordinate clause:

• заявление уже подписано
• можно идти домой

These two ideas belong together under the same что clause.

So the structure is:

• main clause: В отделе кадров мне сказали
• subordinate clause: что заявление уже подписано и можно идти домой

Not always. Заявление can mean several things depending on context, for example:

• application
• statement
• request
• formal written declaration

In an office or HR context, it often means some kind of official written request or form. The exact English word depends on the situation.

So in this sentence, application may be correct, but form or request could also fit depending on the broader context.

Yes, Russian word order is flexible.

This sentence begins with В отделе кадров to set the scene first: In the HR department...

Then мне comes before сказали, which is very natural when the speaker wants to emphasize that the information was given to me.

A more neutral English-like order is not necessary in Russian. You could rearrange parts, but the original sounds natural and smooth:

• В отделе кадров мне сказали...

It starts with the place, then the recipient, then the action.

Russian word order often reflects topic and emphasis more than strict grammar rules.