Доверенность уполномочила председателя голосовать.

Here доверенность means a power of attorney, written authorization, or in some contexts a proxy document.

It is a legal/documentary noun: not a person, but a paper or formal authorization that gives someone the right to act on someone else’s behalf.

So in this sentence, доверенность is the thing that gave the chairman the authority to vote.

Because the subject, доверенность, is a feminine noun.

In the past tense, Russian verbs agree with the subject in gender and number:

• masculine: уполномочил
• feminine: уполномочила
• neuter: уполномочило
• plural: уполномочили

Since доверенность is feminine singular, the verb is уполномочила.

Nouns ending in -ь can be either masculine or feminine, so you often just have to learn their gender.

Доверенность is feminine. One clue is that nouns ending in -ость are almost always feminine:

• возможность
• скорость
• должность
• доверенность

So once you know the pattern, the feminine verb form уполномочила makes sense.

Because it is the direct object of уполномочила, and the verb уполномочить takes a person in the accusative case.

The dictionary form is председатель.
But for a masculine animate noun, the accusative singular looks like the genitive singular:

• nominative: председатель
• accusative: председателя

So доверенность уполномочила председателя = the power of attorney authorized the chairman/chairperson.

Because Russian needs the person being authorized in the accusative case after уполномочить.

The pattern is:

уполномочить + someone (accusative) + infinitive

So:

• уполномочить председателя голосовать = to authorize the chairman to vote
• уполномочить представителя подписать = to authorize the representative to sign

Using председатель here would leave the noun in the nominative, which would be ungrammatical in this sentence.

Because Russian commonly uses an infinitive after verbs like authorize, allow, ask, order, want, etc.

The structure is very similar to English:

• authorized the chairman to vote
• уполномочила председателя голосовать

Russian does not need a separate word matching English to before the second verb. The infinitive itself does the job.

Because Russian infinitives already express that meaning without an extra particle.

English says:

• to vote
• to sign
• to speak

Russian just uses the infinitive form directly:

• голосовать
• подписать
• говорить

So председателя голосовать naturally means the chairman to vote after a verb like уполномочить.

Уполномочить is the perfective verb, and here it makes sense because the sentence describes a completed act of authorization.

The idea is: the document granted the authority; that action happened and is treated as complete.

Compare:

• уполномочила = authorized, granted authority
• уполномочивала = was authorizing / used to authorize / authorized repeatedly (imperfective, depending on context)

In legal or factual statements about a specific authorization, the perfective form is very natural.

The pattern is:

Subject + уполномочить + person in accusative + infinitive

So here:

• Доверенность = subject
• уполномочила = authorized
• председателя = the person authorized
• голосовать = what that person was authorized to do

A useful model sentence is:

• Документ уполномочил представителя подписать договор.
• The document authorized the representative to sign the contract.

Yes. In Russian, just as in formal English, a document can be treated as the thing that legally grants authority.

So Russian can naturally say that the power of attorney authorized someone.

English may sometimes prefer wording like:

• The power of attorney authorized the chairman to vote
• Under the power of attorney, the chairman was authorized to vote

But the Russian structure is perfectly normal.

Yes, Russian word order is flexible, although the given version is straightforward and neutral:

Доверенность уполномочила председателя голосовать.

This order clearly presents:

1. what did the authorizing
2. whom it authorized
3. what they were authorized to do

A different order is sometimes possible for emphasis, but the neutral legal-style wording is the one you have here.

Not always. Председатель often means chairman, chairperson, or chair depending on context.

Grammatically it is a masculine noun, but in translation the best English choice depends on the situation and style:

• chairman if the person is male or the text is traditional
• chairperson or chair if you want gender-neutral English

So the Russian word does not force one single English rendering in every context.

The stress is:

• довере́нность
• уполномо́чила
• председа́теля
• голосова́ть

A rough English-style approximation is:

• da-va-RYE-nnast’
• oo-pal-na-MO-chi-la
• pred-si-DA-ti-lya
• ga-la-sa-VAT’

The exact Russian sounds are different from English, of course, but the stress placement is important to learn early.