İşveren işe alım sırasında ön yazımı istedi.

The sentence follows normal Turkish Subject–Object–Verb order:

İşveren → the employer
işe alım sırasında → during the hiring/recruitment process
ön yazımı → my cover letter
istedi → wanted / asked for

So the verb comes at the end, which is very common in Turkish.

İşveren means employer.

It is historically built from:

• iş = work, job
• veren = giving / the one who gives

So it literally means something like the one who gives work. In modern Turkish, though, you should just learn it as the normal word for employer.

Because the underlying verb is işe almak, which means to hire.

Here:

• iş = work, job
• -e = dative ending, often meaning to / into
• almak = to take

So işe almak is literally something like to take into a job, and that is the standard Turkish expression for to hire.

From that verb, Turkish forms the noun işe alım, meaning hiring or recruitment.

Yes. İşe alım is a very common expression meaning:

• hiring
• recruitment
• the recruitment process

You will often see related phrases like:

• işe alım süreci = the hiring process
• işe alım uzmanı = recruitment specialist

So in this sentence, işe alım sırasında is naturally understood as during the hiring process / at the hiring stage.

Sırasında means during, in the course of, or at the time of.

So:

• işe alım sırasında = during the hiring process

It comes from sıra, which originally has meanings like order, turn, or sequence, but in this pattern it works like a time expression meaning during.

Because it contains two endings:

• ön yazı = cover letter
• -m = my
• -ı = accusative marker, showing it is the specific direct object

So:

• ön yazım = my cover letter
• ön yazımı = my cover letter as the object of the verb

In this sentence, the employer wanted/requested that specific thing, so the accusative is used.

Yes, in a job-application context, ön yazı means cover letter.

Literally, it is something like front writing or introductory writing. In other contexts, it can sometimes mean something closer to foreword or preface, but with words like işveren and işe alım, the meaning is clearly cover letter.

İstedi is the past tense, third person singular form of istemek.

So it means:

• he/she/it wanted
• or, in many contexts, he/she/it asked for / requested

In this sentence, English often sounds more natural with asked for or requested, even though the core verb is the same one used for want.

So İşveren ... ön yazımı istedi can be understood as:

• The employer wanted my cover letter
• The employer asked for my cover letter

Turkish does not have articles like English the and a/an.

Instead, definiteness is usually understood from:

• context
• word order
• case endings
• possession

Here:

• işveren can mean the employer because the context makes it definite
• ön yazımı is clearly specific because it means my cover letter, and it also has the accusative ending

So Turkish does not need separate words like the or a here.

Because possession and case are two different things in Turkish.

• ön yazım = my cover letter
• ön yazımı = my cover letter as a specific direct object

The -m shows whose it is.
The -ı shows its grammatical role in the sentence.

So Turkish can stack both ideas onto the same noun.

Yes. Turkish often leaves out the subject if it is understood from context.

You could say:

İşe alım sırasında ön yazımı istedi.

That would mean something like:

• He/She asked for my cover letter during the hiring process.

But adding İşveren makes the subject explicit and removes ambiguity.

It is closest to during or at the time of.

Important difference:

• sırasında is built from a noun phrase
• it is not a full clause like English while hiring me or while they were hiring

So işe alım sırasında is more like:

• during the hiring process
• at the recruitment stage
• at the time of hiring

Yes:

• İşveren = the employer
• işe alım = hiring / recruitment
• sırasında = during
• ön yazı = cover letter
• -m = my
• -ı = accusative object marker
• istedi = wanted / asked for

So the structure is:

İşveren | işe alım sırasında | ön yazımı | istedi.

That is a very typical Turkish sentence pattern:
subject + time expression + object + verb.