क्या आपके सवाल का जवाब इस कागज़ पर है?

Here क्या is a yes/no question marker, not the word what.

So:

• क्या आपके सवाल का जवाब इस कागज़ पर है? = Is the answer to your question on this paper?

In other sentences, क्या can mean what, but when it appears at the beginning like this, it often just signals that the whole sentence is a yes/no question.

You can sometimes ask a yes/no question without क्या, using rising intonation instead, but क्या is very common and clear.

Because आपका / आपकी / आपके changes to agree with the noun that follows.

Here it is connected to सवाल:

• आपके सवाल = your question

The important point is that सवाल is in the oblique form here, because it is followed by का in सवाल का जवाब.

So the possessive must also take the oblique masculine form:

• आपका सवाल = your question
• आपके सवाल का जवाब = the answer to your question

Even though सवाल itself does not visibly change here, the form आपके shows that oblique relationship.

Because there are two different possession relationships:

1. आपके सवाल = your question
2. सवाल का जवाब = the question's answer / the answer to the question

So the full phrase is layered like this:

• [आपके सवाल] का जवाब
• the answer of [your question]

English uses to in the answer to your question, but Hindi often uses a possession-like structure with का / की / के.

Because इस is the oblique form of यह.

Hindi demonstratives often change form before a postposition:

• यह = this
• इस = this, but before a postposition
• वह = that
• उस = that, before a postposition

Since कागज़ is followed by पर, Hindi uses the oblique form:

• इस कागज़ पर = on this paper

Not यह कागज़ पर.

पर is a postposition meaning on, upon, or sometimes on/in depending on context.

Here:

• इस कागज़ पर = on this paper

With writing, पर often means something is written on a surface or page.

So this sentence is asking whether the answer appears on the paper.

Because पर usually fits better when something is written on a sheet/page/surface.

• कागज़ पर = on the paper
• किताब में = in the book

That said, in some contexts में can be used for documents or written material when you mean inside the contents of something. But with a sheet of paper, पर is the most natural choice.

So:

• इस कागज़ पर है suggests it is written on this paper
• इस कागज़ में है would sound less natural if you mean a physical sheet

A natural breakdown is:

• क्या = yes/no question marker
• आपके सवाल का जवाब = the answer to your question
• इस कागज़ पर = on this paper
• है = is

So literally it is close to:

• Is your question's answer on this paper?

Hindi commonly places the verb at the end, so है comes last.

The main thing being talked about is जवाब:

• आपके सवाल का जवाब = the answer to your question

That whole noun phrase is what है refers to.

So the sentence is essentially saying:

• [The answer to your question] is [on this paper].

Yes. It is polite because it uses आपके, from आप, the respectful/formal word for you.

Compare:

• आपके सवाल का जवाब... = polite/formal
• तुम्हारे सवाल का जवाब... = less formal
• तेरे सवाल का जवाब... = very informal/intimate

So this sentence is appropriate in polite conversation, customer service, teaching, office situations, and so on.

Yes, very common.

• सवाल = question
• जवाब = answer

These are everyday Hindi/Urdu-style words and sound very natural in normal speech.

You could also hear more Sanskrit-based alternatives:

• प्रश्न = question
• उत्तर = answer

So a more formal or textbook-like version could be:

• क्या आपके प्रश्न का उत्तर this कागज़ पर है?

But in ordinary conversation, सवाल and जवाब are extremely common.

कागज़ literally means paper, but depending on context it can refer to:

• a sheet of paper
• a paper/document
• paperwork

In this sentence, it most likely means this paper or this sheet/document.

So the exact English wording may vary slightly by situation:

• on this paper
• on this sheet
• on this document

Yes, you often can, especially in conversation:

• आपके सवाल का जवाब इस कागज़ पर है?

With a questioning tone, this can still mean the same thing.

But starting with क्या makes the yes/no question especially clear, and it is a very standard way to form such questions.