Стандартный вычет и удержанный налог указаны здесь.

Because each word agrees with its own noun:

• стандартный goes with вычет
• удержанный goes with налог

Both вычет and налог are masculine singular nouns, so their modifiers are also masculine singular.

The sentence as a whole has two subjects joined by и (вычет и налог), and that is why the predicate указаны is plural.

Because the subject is compound: вычет и налог = the deduction and the tax.

In Russian, when two singular nouns are joined by и, the predicate is normally plural:

• Вычет и налог указаны здесь. = The deduction and the tax are indicated here.

So указаны is plural to match both items together.

Указаны is the short-form passive participle of указать.

A very natural way to understand it is:

• указан / указана / указано / указаны
  = indicated / listed / stated / shown

In this sentence, it works like a predicate, similar to English are indicated or are listed.

Compare:

• указанный = full form, used like an adjective before a noun
• указаны = short form, used as part of the predicate

For example:

• указанный налог = the indicated tax
• налог указан здесь = the tax is indicated here

Удержанный is also a passive participle, from the verb удержать.

In tax/payroll language, удержанный налог means:

• withheld tax
• literally, tax that has been withheld

So it describes the noun налог.

This is very common in formal or administrative Russian, where participles are used like adjectives.

Because they are the subject of the sentence.

The structure is basically:

• Стандартный вычет и удержанный налог = the subject
• указаны здесь = the predicate

Since they are the things being indicated/listed, they stay in the nominative.

A learner might expect some other case because English often uses fixed word order instead of endings, but here Russian is simply marking the subject in the normal way.

In a sentence like this, it is best understood as a present-state result:

• are indicated here
• are listed here

Short passive participles often describe the current state resulting from an action, not a simple past event.

So указаны здесь does not mainly mean were indicated here. In this context it means that, on this page or in this place, these items are shown/listed.

This is very common in forms, documents, and interfaces.

Yes, Russian word order is flexible, so здесь can move.

All of these are possible:

• Стандартный вычет и удержанный налог указаны здесь.
• Здесь указаны стандартный вычет и удержанный налог.
• Стандартный вычет и удержанный налог здесь указаны.

The version with здесь at the end sounds natural and straightforward, especially in UI, form, or document language.

Putting здесь first often gives a little more emphasis to here:

• Здесь указаны... = Here are listed...

Вычет is a formal word meaning deduction, especially in financial or tax contexts.

So стандартный вычет is a set phrase meaning standard deduction.

This is not the everyday verb-like idea of subtracting in a math sentence, although it is related historically. In administrative language, вычет is a noun used for a legal or tax deduction.

Russian has no articles.

So:

• стандартный вычет can mean a standard deduction or the standard deduction
• удержанный налог can mean withheld tax or the withheld tax

The exact meaning depends on context.

In a form or document, the reader usually already knows which deduction and tax are meant, so English often uses the, while Russian simply does not need an article.

Yes, but the original sounds more natural in formal written Russian.

A possible rewording is:

• Здесь указываются стандартный вычет и удержанный налог.

This means something like:

• The standard deduction and withheld tax are shown/listed here.

However, указываются can sound more like a general process or routine action, while указаны sounds like a present result on a page, form, or screen: they are listed here.

That is why указаны is especially common in official and interface language.

The main stress is:

• станда́ртный
• вы́чет
• удержа́нный
• нало́г
• указа́ны
• здесь

A rough pronunciation guide:

• станда́ртный = stan-DART-nyy
• вы́чет = VY-chet
• удержа́нный = oo-der-ZHAN-nyy
• нало́г = na-LOG
• указа́ны = oo-ka-ZA-ny
• здесь = zdehs

The cluster in здесь can be hard for English speakers, so it helps to practice it slowly.

Then указаны would change to the singular form that matches the noun.

For example:

• Стандартный вычет указан здесь.
• Удержанный налог указан здесь.

The short-form participle changes like this:

• указан — masculine singular
• указана — feminine singular
• указано — neuter singular
• указаны — plural

So in your sentence, plural указаны is required because there are two items.