Prosím, vyplňte formulář.

Vyplňte is the imperative form of the verb vyplnit, which means to fill in / to complete.

In this sentence, vyplňte means fill in or complete.

It is the form used for:

• you (plural), or
• formal you (singular or plural)

So Vyplňte formulář. is a polite instruction: Please fill in the form.

Czech has different imperative forms depending on who you are speaking to.

• vyplň = informal singular command, used with one person you know well
• vyplňte = formal singular or plural command

So:

• Vyplň formulář. = Fill in the form. (to one friend, informal)
• Vyplňte formulář. = Fill in the form. (formal, or to more than one person)

In customer service, offices, hospitals, hotels, and similar situations, vyplňte is the normal polite choice.

Prosím usually means please, but its exact function depends on context.

In Prosím, vyplňte formulář., it softens the command and makes it polite:

• Prosím, vyplňte formulář. = Please fill in the form.

You will also hear prosím used in other ways, for example:

• Prosím. = Here you are / yes? / go ahead
• Prosím vás... = Excuse me... / please...
• Ano, prosím. = Yes? / How can I help?

So here it is simply the polite please.

In Czech, subject pronouns are often omitted because the verb ending already shows who the subject is.

Here, vyplňte already tells you that the command is for:

• you plural, or
• formal you

So Czech does not need to say vy explicitly.

You could say Vyplňte formulář, but normally the pronoun is left out unless you want emphasis or contrast.

Formulář is the direct object of the verb vyplnit, so it is in the accusative case.

For this noun, the nominative and accusative singular forms are the same:

• nominative: formulář
• accusative: formulář

So although the noun is functioning as an object, its form does not visibly change here.

This is very common in Czech with many masculine inanimate nouns.

Formulář is a masculine inanimate noun.

Yes, that matters because:

• it affects how the noun declines in different cases
• it affects agreement with adjectives, pronouns, and numerals

For example:

• ten formulář = that form
• vyplňte tento formulář = fill in this form

Because it is masculine inanimate, its accusative singular often looks the same as the nominative.

Vyplnit is a perfective verb.

That matters because perfective verbs in Czech often express completing an action as a whole. In instructions like this, that is very natural:

• vyplnit formulář = to fill in the form completely

The imperfective partner is usually vyplňovat:

• vyplňovat formulář = to be filling in a form / to fill in forms repeatedly or as a process

For a one-time instruction, especially in practical situations, the perfective vyplňte is the normal choice.

It is possible grammatically, but it would usually sound less natural in this situation.

• Vyplňte formulář. = Please fill in the form.
  This is the normal instruction when someone wants the completed result.

• Vyplňujte formulář. = Please be filling in the form / fill in the form repeatedly / keep filling in the form.
  This sounds more process-oriented, repeated, or ongoing.

In an office or reception setting, vyplňte formulář is the standard phrase.

In Czech, the main stress is usually on the first syllable of each word.

So:

• PRO-sím
• VY-plň-te
• FOR-mu-lář

A rough English-friendly pronunciation:

• Prosím ≈ PRO-seem
• vyplňte ≈ VI-plnyeteh or VI-plny-teh
  The plň cluster is tricky for English speakers.
• formulář ≈ FOR-moo-laarzh

A few pronunciation notes:

• í is a long vowel
• á is a long vowel
• ř in formulář is the famous Czech sound, difficult for learners; an approximation like zh is acceptable at first
• ň is like the ny sound in canyon

Because prosím is being used as a separate polite word, almost like a discourse marker: Please, ...

So the punctuation:

• Prosím, vyplňte formulář.

is standard and natural.

In real-life writing, especially on signs or forms, you may sometimes see punctuation used less carefully, but with normal standard punctuation, the comma is a good choice here.

Yes, Czech word order is flexible, but not every version sounds equally natural.

The most natural neutral version is:

• Prosím, vyplňte formulář.

You could also hear:

• Vyplňte prosím formulář.
• Formulář prosím vyplňte.

These all mean roughly the same thing, but the emphasis changes slightly.

For a standard polite instruction, the most common versions are:

• Prosím, vyplňte formulář.
• Vyplňte prosím formulář.

Yes, absolutely. This is a very normal sentence in places like:

• offices
• clinics
• hotels
• schools
• government buildings
• reception desks

It sounds polite, standard, and natural.

Depending on tone and situation, a Czech speaker might also say:

• Vyplňte prosím formulář.
• Prosím vás, vyplňte formulář.
• Mohl byste vyplnit formulář? = Could you fill in the form?
• Můžete prosím vyplnit formulář? = Can you please fill in the form?

The original sentence is simple, direct, and perfectly idiomatic.

These words are related, but they are not identical.

• formulář = form
  A general blank document to fill in

• dotazník = questionnaire / survey
  A list of questions

• přihláška = application form / registration form
  A specific kind of form used to apply or sign up

So vyplňte formulář is a general instruction. If the document type is more specific, Czech might use one of those other words instead.