Po doręczeniu sprawdzam, czy ktoś uszkodził opakowanie lub zawartość.

Because the preposition po here means after, and in this use it requires the locative case.

• doręczenie = nominative/basic form, delivery
• po doręczeniu = after the delivery

So the ending changes because of grammar, not because the meaning changes.

Doręczeniu is the locative singular form of doręczenie, a verbal noun meaning delivery, serving, or handing over.

In this sentence, po doręczeniu means something like:

• after delivery
• once it has been delivered

It sounds a bit formal, which fits contexts like parcels, official documents, or shipments.

Sprawdzam is the 1st person singular present form of sprawdzać (to check).

Polish present tense can describe:

• a habitual action: After delivery, I check...
• a standard procedure: Once delivery happens, I check...
• something happening now in a live description

So sprawdzam works naturally for English I check.

Also, Polish often leaves out the subject pronoun ja, because the verb ending already shows who is doing the action.

• sprawdzam = I check

Because Polish usually does not need subject pronouns when the verb already makes the subject clear.

• sprawdzam clearly means I check

Adding ja is possible, but it usually adds emphasis:

• Ja sprawdzam = I am the one who checks

Without emphasis, simply sprawdzam is more natural.

Here czy means whether or if.

It introduces an indirect yes/no question:

• sprawdzam, czy... = I check whether...

This is different from czy at the start of a direct yes/no question:

• Czy to działa? = Does it work?

In your sentence, it is not asking the listener a question. It is reporting what the speaker checks.

Because the damage, if it happened, would have happened before the checking.

So the timeline is:

1. delivery happens
2. I check
3. I check whether someone damaged the packaging or contents earlier

That is why Polish uses uszkodził (damaged) rather than a present-tense form.

In Polish, when the subject is an unspecified someone (ktoś), the past tense often appears in the masculine singular form by default:

• ktoś uszkodził = someone damaged

This does not necessarily mean the person was male. It is just the normal default form in this structure.

If the person were known to be female, you could say:

• ktoś uszkodziła — but this is much less standard unless the feminine identity is specifically established in context

For learners, it is best to remember:

• ktoś zrobił
• ktoś powiedział
• ktoś uszkodził

These are the normal patterns.

Uszkodzić is the perfective verb, and uszkodził presents the damage as a completed event:

• someone damaged it

That makes sense here because you are checking whether any actual damage occurred.

The imperfective partner is uszkadzać, but that would suggest repeated or ongoing damaging, which does not fit as well in this sentence.

So:

• uszkodził = damaged / has damaged as a completed act

They are in the accusative case because they are the direct objects of uszkodził.

The verb answers the question damaged what?

• opakowanie = packaging
• zawartość = contents

Their forms here are:

• opakowanie — neuter; nominative and accusative singular look the same
• zawartość — feminine; nominative and accusative singular also look the same in this noun

So even though the forms do not visibly change, they are functioning as accusative objects.

They refer to two different things:

• opakowanie = the packaging, outer container, wrapping, box, etc.
• zawartość = the contents, what is inside

So the sentence means the speaker checks both:

1. whether the outside was damaged
2. whether what is inside was damaged

Both lub and albo can mean or.

The main difference is style:

• lub sounds a bit more formal or written
• albo is often more everyday and conversational

So:

• opakowanie lub zawartość = a slightly more formal phrasing
• opakowanie albo zawartość would also be understandable and natural

In a sentence about delivery and inspection, lub fits well.

Yes, sometimes, but the nuance can change.

• doręczenie often suggests official delivery, serving, or successful delivery to the recipient
• dostarczenie is more general: delivering, bringing, supplying

In parcel or document language, doręczenie can sound more precise and formal.
So po doręczeniu is a good choice if the sentence is about a completed delivery to the recipient.

No, Polish word order is fairly flexible, but the original order is natural and clear.

Original:

• Po doręczeniu sprawdzam, czy ktoś uszkodził opakowanie lub zawartość.

You could also rearrange parts for emphasis, for example:

• Sprawdzam po doręczeniu, czy ktoś uszkodził opakowanie lub zawartość.

But the original version is probably the most straightforward:

• first the time phrase
• then the main action
• then the czy clause

So the word order is not completely fixed, but it is well chosen.