Umowa zawarta na odległość obejmuje koszt dostawy i koszt odesłania.

Because zawarta agrees with umowa, and umowa is a feminine singular noun.

• umowa = contract/agreement
• zawarty / zawarta / zawarte = concluded, entered into

The participle has to match the noun in gender and number:

• umowa zawarta = a contract concluded
• dokument zawarty would be wrong, because dokument is masculine
• porozumienie zawarte would be neuter

So zawarta is the feminine singular form.

Zawarta is a passive past participle from the verb zawrzeć (to conclude, to enter into an agreement/contract).

In this sentence, umowa zawarta na odległość literally means something like:

• a contract concluded at a distance
• more naturally: a distance contract or a contract concluded remotely

This kind of participle is very common in formal and legal Polish.

Na odległość is a fixed expression meaning remotely, at a distance, or without physical presence.

Literally:

• na = on/at
• odległość = distance

But you should learn na odległość as a set phrase. In legal or commercial language, umowa zawarta na odległość is the standard expression for a contract made without the parties being physically together, for example online or by phone.

Here na takes the accusative, and for this noun the nominative and accusative singular happen to look the same:

• nominative: odległość
• accusative: odległość

So the case does change in function, but not in visible form.

This is common with many feminine nouns ending in -ość.

Obejmuje means includes, covers, or encompasses.

It is the 3rd person singular form of obejmować:

• (ta umowa) obejmuje = (this contract) includes

Because the subject umowa is singular, the verb is singular too.

Because after koszt (cost), Polish usually puts the thing being paid for in the genitive.

So:

• koszt dostawy = cost of delivery
• koszt odesłania = cost of sending back / return shipping cost

The base forms are:

• dostawa → genitive dostawy
• odesłanie → genitive odesłania

This is very normal in Polish noun phrases:

• cena produktu = price of the product
• numer telefonu = phone number
• koszt przesyłki = cost of shipment

They refer to opposite directions of shipping:

• dostawa = delivery, sending something to the customer
• odesłanie = sending something back, returning it

So in this sentence:

• koszt dostawy = delivery cost
• koszt odesłania = return cost / cost of sending it back

Here it is a noun.

It comes from the verb odesłać = to send back.

Polish often creates nouns from verbs in this way:

• odesłać = to send back
• odesłanie = sending back / return

So koszt odesłania literally means the cost of the sending back.

Because Polish has no articles.

So umowa can mean:

• a contract
• the contract

The exact meaning depends on context.

That is normal in Polish, and learners from English often notice it right away.

Not completely. Polish word order is more flexible than English, because case endings show grammatical relationships.

The given sentence is natural and neutral:

• Umowa zawarta na odległość obejmuje koszt dostawy i koszt odesłania.

But other orders are possible for emphasis, for example:

• Koszt dostawy i koszt odesłania obejmuje umowa zawarta na odległość.

That sounds more formal or marked. The original version is the clearest and most standard.

Yes, in some contexts Polish might avoid repeating koszt:

• obejmuje koszt dostawy i odesłania

This can sound fine, especially if both items are clearly parallel.

However, repeating koszt makes the phrase very explicit and formal, which fits legal or policy language well:

• koszt dostawy i koszt odesłania

Yes. It is a standard legal/consumer-law expression.

It refers to a contract concluded without the physical presence of both parties, typically:

• online
• by phone
• by mail

So although each word is understandable on its own, the whole phrase functions as a set legal term.

Because the subject of the sentence is umowa zawarta na odległość, not the two costs.

Structure:

• Umowa ... obejmuje ... = The contract ... includes ...

The two costs are the object of the verb, not the subject.

So singular obejmuje is correct.

A useful breakdown is:

• Umowa — nominative singular
  (the subject)

• zawarta — agrees with umowa
  (feminine singular nominative form)

• na odległość — accusative after na in this fixed phrase

• obejmuje — verb

• koszt dostawy i koszt odesłania — accusative as the direct object
  but koszt is masculine inanimate, so nominative and accusative look the same

Inside those noun phrases:

• dostawy — genitive singular
• odesłania — genitive singular

So English speakers often do not “see” all the case changes immediately, because some forms are identical on the surface.

Yes. The sentence sounds formal, administrative, or legal.

Clues include:

• umowa zawarta na odległość — legal terminology
• obejmuje — formal includes/covers
• repeated koszt — explicit, careful wording

In everyday speech, a person might say something simpler, but this version is very natural in regulations, terms and conditions, or consumer-rights information.