Jeśli chcesz zrobić zwrot, nie odcinaj metki i zachowaj pudełko.

Jeśli means if. Yes, jeżeli also means if and is very close in meaning.

• jeśli = very common, neutral
• jeżeli = also common, sometimes a bit more formal or careful in tone

So Jeśli chcesz zrobić zwrot... and Jeżeli chcesz zrobić zwrot... are both correct.

After chcieć (to want), Polish uses the infinitive of the next verb.

So:

• chcesz zrobić = you want to do/make
• literally: you want + to do

This is the same pattern as:

• chcę kupić = I want to buy
• chcemy wrócić = we want to return

So zrobić stays in the infinitive, not a personal form like zrobisz.

Here zwrot is a noun meaning return in a shopping context. So zrobić zwrot is literally to make/do a return.

It is understandable and natural enough, especially in everyday language. But Polish also often uses:

• dokonać zwrotu = to make a return, more formal
• zwrócić towar / produkt = to return the goods/product

So this sentence is fine, but you may also see other versions in stores or regulations.

Yes. These are imperative forms addressed to one person, the informal ty form.

• nie odcinaj = don’t cut off
• zachowaj = keep / save

Even when stores are speaking to customers in general, Polish often uses this singular command form in instructions.

If you wanted the plural/informal you all form, you would say:

• nie odcinajcie
• zachowajcie

A polite singular form would usually be expressed differently, for example:

• proszę nie odcinać metki
• proszę zachować pudełko

This is a very common Polish pattern.

• Negative commands often use the imperfective verb: nie odcinaj
• Positive commands often use the perfective verb when you want one completed result: zachowaj

So:

• nie odcinaj = don’t do that action at all
• zachowaj = make sure you keep it

This sounds natural in Polish. A learner may expect the same kind of verb in both places, but Polish often mixes aspects like this in instructions.

Because after negation, Polish very often uses the genitive instead of the accusative for a direct object.

Without negation, you would expect metkę:

• odetnij metkę = cut off the tag

But with nie, standard Polish prefers:

• nie odcinaj metki = don’t cut off the tag

So here:

• metka = dictionary form
• metki = genitive singular

This is one of the classic things English speakers notice, because English does not change the object after negation in this way.

Pudełko is the direct object of zachowaj, so it is in the accusative.

The reason it looks unchanged is that for many neuter nouns in singular, the nominative and accusative forms are the same.

So:

• pudełko = nominative singular
• pudełko = accusative singular

That is why the form stays pudełko.

Because Jeśli chcesz zrobić zwrot is a subordinate clause introduced by jeśli (if), and it is separated from the main clause by a comma.

Structure:

• Jeśli chcesz zrobić zwrot, = if you want to make a return
• nie odcinaj metki i zachowaj pudełko. = don’t cut off the tag and keep the box

This comma is standard Polish punctuation.

Polish word order is fairly flexible, so other versions are possible.

For example:

• Jeśli chcesz zrobić zwrot, zachowaj pudełko i nie odcinaj metki.
• Nie odcinaj metki i zachowaj pudełko, jeśli chcesz zrobić zwrot.

The original order is natural and clear. It puts the condition first, then gives the instructions. The order of the two commands can be changed depending on emphasis.

Not exactly.

Metka usually means a tag attached to clothes or products, often the kind you remove before using the item. It can be a paper tag or a sewn-in tag, depending on context.

Etykieta more often means a label, for example on a bottle, package, or product surface.

In this sentence, metka is the natural word because stores often mean the attached product tag that should remain on the item for a return.

A simple English-style approximation:

• jeśli ≈ YESH-lee
• chcesz ≈ something like hchesh or h-chesh; it is compact and tricky for beginners
• zwrot ≈ zvrot
• zachowaj ≈ za-HO-vai
• pudełko ≈ poo-DEL-ko

A few useful notes:

• ś in jeśli is a soft sh-like sound
• ch in chcesz is like a hard h
• rz in zwrot sounds like zh in many contexts, but after certain consonants it may sound more like sh
• Polish stress is usually on the second-to-last syllable: JE-śli, za-CHO-waj, pu-DEŁ-ko