ग्राहक बैंक शाखा में है।

Because Hindi normally puts the main verb at the end. A very common basic pattern is:

subject + place/time/other information + verb

So:

ग्राहक + बैंक शाखा में + है

This is one of the first big word-order differences English speakers notice, since English usually puts is earlier.

में is a postposition meaning in or inside.

English uses a preposition before the noun:

• in the bank branch

Hindi uses a postposition after the noun phrase:

• बैंक शाखा में

So Hindi says the equivalent of bank branch in.

Because Hindi postpositions come after the noun phrase they belong to.

So:

• शाखा में = in the branch
• घर में = in the house
• कक्षा में = in the classroom

Putting में before the noun would sound ungrammatical in standard Hindi.

Hindi usually does not use articles the way English does.

So a sentence like this can often mean:

• the customer is in the bank branch
• a customer is in the bank branch
• sometimes just customer is in the bank branch, depending on context

Context usually tells you whether the noun is definite or indefinite.

Yes, बैंक शाखा works as a noun-noun combination meaning bank branch.

You can also say बैंक की शाखा, which is more explicitly the branch of the bank.

Very roughly:

• बैंक शाखा = compact, institutional, label-like
• बैंक की शाखा = more fully spelled out

Both are understandable. In many formal or official contexts, noun compounds like बैंक शाखा are common.

Good question. In Hindi, nouns often take an oblique form before postpositions like में, पर, से, का/की/के.

But not all nouns change visibly.

शाखा is a feminine noun, and its singular direct and singular oblique forms are the same:

• direct: शाखा
• oblique singular: शाखा

So before में, it still looks like शाखा.

Compare that with a masculine -ा noun, which often does change:

• लड़का → लड़के में

It goes with the whole clause, but in practical terms it matches the subject, which here is ग्राहक.

So:

• ग्राहक ... है = singular
• ग्राहक ... हैं = plural or respectful singular, depending on context

It does not agree with शाखा, even though शाखा is the noun right before में. The phrase बैंक शाखा में is just a location phrase.

The form ग्राहक itself can be tricky, because many Hindi nouns do not change much in the plural.

What tells you it is singular here is है.

• ग्राहक ... है = the customer is
• ग्राहक ... हैं = the customers are or sometimes the customer is with respectful आप-style agreement

So the verb is the main clue.

• शाखा is a feminine noun.
• ग्राहक is usually treated as masculine in traditional grammar, though in real usage it can refer to a customer generally and context may determine the person’s sex.

In this sentence, gender does not visibly affect है, because present-tense है does not change for masculine vs feminine.

So:

• पुरुष ग्राहक बैंक शाखा में है
• महिला ग्राहक बैंक शाखा में है

The verb stays है if the subject is singular.

A simple transliteration is:

grāhak baiṅk śākhā meṅ hai

A few pronunciation notes:

• ग्राहक = grā-hak
• बैंक has an ai sound, roughly like the vowel in bank is not right; it is closer to baink
• शाखा = shaa-khaa
• में = meṅ, with nasalization at the end
• है = hai, often sounding roughly like high

If you want a more learner-friendly version, you can think: graahak baink shaakhaa mein hai

Yes. That would mean the customer is in the bank.

The difference is:

• बैंक में = in the bank
• बैंक शाखा में = in the bank branch

So the original sentence is a bit more specific or formal. If the branch idea is not important, ग्राहक बैंक में है is perfectly natural.