Wpisuję adres i numer telefonu do formularza.

Wpisuję means I am entering, I enter, or I write in/fill in, depending on context.

It comes from the verb wpisywać (imperfective). This verb is used when you put information into something such as:

• a form
• a list
• a document
• a box on a screen

So Wpisuję adres i numer telefonu do formularza means that you are entering those details into the form.

A useful contrast is:

• wpisywać / wpisuję — imperfective, focusing on the process or repeated action
• wpisać / wpiszę — perfective, focusing on completing the action

So:

• Wpisuję adres... = I’m entering the address...
• Wpiszę adres... = I will enter the address / I’ll write in the address

In Polish, subject pronouns are often omitted because the verb ending already tells you who is doing the action.

Here, -ę in wpisuję tells you it is I.

So:

• Wpisuję = I enter / I am entering
• Ja wpisuję = I enter, with extra emphasis

You would usually add ja only if you want contrast or emphasis, for example:

• Ja wpisuję adres, a ty wpisujesz numer telefonu.
  I enter the address, and you enter the phone number.

They are in the accusative case because they are the direct objects of the verb wpisuję — they are the things being entered.

However, for many masculine inanimate nouns in the singular, the accusative looks exactly the same as the nominative.

So:

• nominative: adres
• accusative: adres

and

• nominative: numer
• accusative: numer

That is why they do not visibly change here.

Because after numer, Polish normally uses the genitive for the thing that the number belongs to.

So:

• numer telefonu = phone number
• literally: number of the phone

This is a very common Polish pattern:

• numer pokoju = room number
• numer paszportu = passport number
• numer konta = account number

So telefonu is the genitive singular of telefon.

Because the preposition do requires the genitive case.

So:

• formularz = nominative
• formularza = genitive

That is why you say:

• do formularza = into the form / to the form

This is a general rule in Polish: when you use do, the noun after it normally goes into the genitive.

This is a very useful distinction.

• do formularza suggests putting something into the form
• w formularzu means in the form

So with a verb like wpisywać (to enter/write in), do formularza is very natural because you are adding information into it.

Compare:

• Wpisuję adres do formularza.
  I’m entering the address into the form.

• W formularzu jest błąd.
  There is a mistake in the form.

In other words:

• do = direction, insertion, putting something in
• w = location, being inside

No, Polish word order is fairly flexible.

The sentence:

• Wpisuję adres i numer telefonu do formularza.

is a neutral, natural order.

But you can move things around to change emphasis:

• Do formularza wpisuję adres i numer telefonu.
  Emphasis on into the form

• Adres i numer telefonu wpisuję do formularza.
  Emphasis on the address and phone number

All of these can be correct. The most natural version depends on what information is new, important, or contrasted.

Because Polish has no articles. There is no direct equivalent of English a/an or the.

So adres can mean:

• an address
• the address
• address

The exact meaning depends on context.

If you want to make it clearer whose address it is, you can add a possessive word, for example:

• Wpisuję mój adres i numer telefonu do formularza.
  I am entering my address and phone number into the form.

Very often, though, Polish leaves this unstated if it is already obvious.

Piszę simply means I write.

Wpisuję is more specific: it means I write/enter something into a particular place such as a form, list, register, or box.

Compare:

• Piszę list.
  I am writing a letter.

• Wpisuję adres do formularza.
  I am entering the address into the form.

So in this sentence, wpisuję is the better verb because the idea is not just writing in general, but putting information into a form.

Yes, but it is not exactly the same.

• Wpisuję adres i numer telefonu do formularza.
  I am entering the address and phone number into the form.

• Wypełniam formularz.
  I am filling out the form.

Wypełniam formularz is broader: it means completing the form as a whole.
Wpisuję... do formularza focuses on the specific information being entered.

You can even combine the ideas:

• Wypełniam formularz, wpisując adres i numer telefonu.
  I am filling out the form by entering the address and phone number.

It is singular.

• telefon = phone
• telefonu = of the phone / phone’s

So numer telefonu means phone number in the singular.

If you wanted phone numbers, you would need a different structure, for example:

• numery telefonów = phone numbers

In your sentence, it clearly means one address and one phone number.

It can mean either, depending on context.

Because wpisuję is present tense imperfective, it can mean:

• I am entering the address and phone number into the form — right now
• I enter the address and phone number into the form — habitually or as a general description

Context tells you which meaning is intended.

For example:

• Teraz wpisuję adres i numer telefonu do formularza.
  Now I’m entering the address and phone number into the form.

• Zawsze wpisuję adres i numer telefonu do formularza.
  I always enter the address and phone number into the form.