इस काम का मकसद क्या है?

Because इस is the oblique form of यह.

In Hindi, when a noun phrase is followed by a postposition such as का, को, में, से, etc., words like यह / वह usually change to their oblique forms:

• यह → इस
• वह → उस

So:

• यह काम = this work/task
• इस काम का... = of this work/task...

Here, the phrase इस काम is followed by का, so यह becomes इस.

Because का / की / ke agrees with the noun that comes after it here, namely मकसद.

मकसद is treated as masculine singular, so the correct form is का:

• इस काम का मकसद = the purpose of this work

Compare:

• इस काम की वजह = the reason for this work
  because वजह is feminine
• इन कामों के मकसद = the purposes of these tasks
  because मकसद is plural there

So in this sentence, का matches मकसद.

In Hindi, question words often stay in the place where the answer would normally go.

Statement:

• इस काम का मकसद है... = The purpose of this work is...

Question:

• इस काम का मकसद क्या है? = What is the purpose of this work?

So क्या appears where the missing information goes.

This is different from sentence-initial क्या, which is often used for yes/no questions:

• क्या तुम आ रहे हो? = Are you coming?

But here क्या means what, so it stays in the slot of the thing being asked about.

मकसद means purpose, aim, objective, or sometimes motive, depending on context.

In this sentence, it most naturally means:

• purpose
• aim
• objective

It is a very common everyday word. A slightly more formal/Sanskrit-based alternative is उद्देश्य:

• इस काम का उद्देश्य क्या है?

That means almost the same thing, but उद्देश्य sounds a bit more formal or official.

It can mean any of those, depending on context.

काम is a broad word. It may refer to:

• work
• task
• job
• activity
• thing being done

So इस काम का मकसद क्या है? could be understood as:

• What is the purpose of this work?
• What is the purpose of this task?
• What is the point of this job/activity?

The exact English choice depends on the situation.

There isn’t one, because Hindi does not usually use articles like English a/an/the.

So Hindi often leaves that idea to context.

• इस काम का मकसद क्या है?

Depending on context, this could correspond to:

• What is the purpose of this work?
• What is the purpose of the task?
• What is the aim of this job?

Hindi speakers do not need separate words for a and the in most cases.

Yes, in standard Hindi this sentence normally takes है.

है is the present-tense form of to be here:

• इस काम का मकसद क्या है? = What is the purpose of this work?

If you remove है, it may sound incomplete in standard written Hindi. In very casual speech, people sometimes drop forms of to be, but learners should keep है here.

A very literal breakdown is:

• इस = this (oblique form)
• काम = work/task
• का = of
• मकसद = purpose
• क्या = what
• है = is

So, very literally:

• This work of purpose what is?

But natural English is:

• What is the purpose of this work?

Hindi often puts the possessor/related noun first and then uses का/की/के to link it to the main noun.

You would use उस instead of इस:

• उस काम का मकसद क्या है? = What is the purpose of that work/task?

This follows the same pattern:

• यह → इस
• वह → उस

So:

• यह काम = this task
• इस काम का... = of this task
• वह काम = that task
• उस काम का... = of that task

A common transliteration is:

is kaam ka maksad kya hai?

Rough pronunciation:

• इस = is
• काम = kaam (long aa sound)
• का = kaa
• मकसद = maksad or sometimes close to maqsad
• क्या = kyaa
• है = hai

So the whole sentence sounds roughly like:

is kaam kaa mak-sad kyaa hai?

The aa in काम and का is longer than the vowel in English cup or cat.