Erişim kartı kiralık depo için kullanıldı.

A word-by-word breakdown is:

• erişim = access
• kartı = card, but here it is part of the fixed noun phrase erişim kartı = access card
• kiralık = rental / for rent
• depo = storage unit, depot, warehouse, or storage room depending on context
• için = for
• kullanıldı = was used

So the structure is roughly:

• Erişim kartı = access card
• kiralık depo için = for the rental storage unit / for the rented storage space
• kullanıldı = was used

Because erişim kartı is a very common Turkish noun compound.

In Turkish, when one noun modifies another noun, the second noun often takes the 3rd person possessive ending. So:

• erişim = access
• kart = card
• erişim kartı = access card

This does not mean his/her card here. It is just how many noun compounds are formed in Turkish.

Other examples:

• kredi kartı = credit card
• kimlik kartı = ID card
• otobüs durağı = bus stop

So in this sentence, kartı is part of the compound, not an accusative ending.

No. In this sentence, erişim kartı is the subject.

Why? Because kullanıldı is passive:

• kullanmak = to use
• kullanıldı = was used

So the sentence is literally structured like:

• The access card
  • was used
    • for the rental storage unit

If the sentence were active, you might have something like:

• Görevli erişim kartını kullandı.
• The staff member used the access card.

There, kartını would be the object. But in your original sentence, the passive makes erişim kartı the subject.

Kullanıldı comes from:

• kullan- = use
• -ıl- = passive marker
• -dı = past tense

So:

• kullanmak = to use
• kullanılmak = to be used
• kullanıldı = was used

This is a very common pattern in Turkish:

• açmak = to open
• açıldı = was opened / opened
• yapmak = to do, make
• yapıldı = was done / was made
• satmak = to sell
• satıldı = was sold

İçin usually means for.

In this sentence, kiralık depo için means for the rental storage unit or for use with the rental storage unit.

It shows purpose or intended relation:

• senin için = for you
• ders için = for class
• iş için = for work

So here it tells us what the access card was used for.

Kiralık usually means for rent, rental, or meant to be rented.

It comes from kira = rent, with a suffix that often creates adjectives.

Examples:

• kiralık ev = house for rent / rental house
• kiralık araba = rental car
• kiralık depo = rental storage unit / storage space for rent

A useful nuance:

• kiralık often describes something as a rental item or rentable property
• kiralanmış would mean rented in the sense of already rented

So kiralık depo is more like rental storage than explicitly a storage unit that has already been rented.

Yes. Turkish usually puts the verb at the end, so this word order is very normal:

• Erişim kartı kiralık depo için kullanıldı.

That is a neutral, standard structure.

You could rearrange parts for emphasis, for example:

• Kiralık depo için erişim kartı kullanıldı.

This still means essentially the same thing, but it puts more focus on kiralık depo için.

In Turkish, word order is flexible, but the most neutral place for the verb is usually the end.

Turkish does not have a definite article like English the.

And the indefinite article a/an is often expressed with bir, but only when needed.

So:

• depo can mean a storage unit, the storage unit, or just storage unit, depending on context.
• erişim kartı can mean an access card or the access card, depending on context.

If you wanted to make it clearly indefinite, you could say:

• Bir erişim kartı kiralık depo için kullanıldı.
• An access card was used for the rental storage unit.

But without bir, Turkish often leaves that choice to context.

It can mean either, depending on context.

Depo is a broad word that can refer to:

• a warehouse
• a storage room
• a depot
• a storage unit

In a sentence with erişim kartı and kiralık, many learners would naturally understand kiralık depo as something like:

• rental storage unit
• rented storage space
• possibly rental warehouse, if the context is commercial

So the best English translation depends on the situation, not just the grammar.

Yes. The original sentence is grammatical, but Turkish often allows you to be more explicit if needed.

For example:

• Erişim kartı kiralık depoya girmek için kullanıldı.
• The access card was used to enter the rental storage unit.

or

• Erişim kartı kiralık depoya erişim için kullanıldı.
• The access card was used for access to the rental storage unit.

These versions make the relationship clearer. The original sentence is shorter and more general.

Yes, it is understandable and grammatically fine.

That said, depending on context, a native speaker might prefer a slightly more specific version if they want to show exactly how the card was used, for example:

• Erişim kartı kiralık depoya giriş için kullanıldı.
• The access card was used for entry to the rental storage unit.

Your original sentence is still valid. It just leaves the exact kind of use a little broader.

The biggest points are:

1. Turkish noun compounds

   • erişim kartı = access card
   • the second noun often gets a possessive-looking ending

2. Passive verb formation

   • kullanıldı = was used

3. Postpositions instead of prepositions

   • için comes after the noun phrase
   • Turkish says something like rental storage for, not for rental storage

4. Verb-final order

   • The main verb usually comes at the end

5. No articles like English

   • Turkish often leaves a/the to context

This sentence is a nice example of several very common Turkish patterns all at once.