Họ phát hành thẻ ở chi nhánh.

• Họ = they
• phát hành = issue, release, or publish, depending on context
• thẻ = card
• ở = at, in, or to a place, depending on context
• chi nhánh = branch or branch office

So the sentence structure is basically:

Họ + phát hành + thẻ + ở chi nhánh
= They issue cards at the branch.

In this sentence, họ means they.

A native English speaker might expect Vietnamese to always specify exactly who they are, but Vietnamese often uses họ the same way English does when the people are already understood from context.

A few notes:

• họ is a third-person plural pronoun: they / them
• It does not show gender
• It can sound a little formal or neutral compared with some everyday omitted-subject sentences

In real life, Vietnamese often drops the subject entirely if it is obvious from context. So you may also hear:

• Phát hành thẻ ở chi nhánh.
  = [They/We/Someone] issue cards at the branch, depending on context.

Yes. In this sentence, phát hành is best understood as issue.

However, phát hành is a fairly broad term. It can also mean:

• publish a book
• release a movie, album, or product
• issue a document, card, or ticket

So the exact English translation depends on the object:

• phát hành sách = publish books
• phát hành vé = issue tickets
• phát hành thẻ = issue cards

In a banking or administrative context, phát hành thẻ is very natural for issuing a card.

Because Vietnamese often does not need an article like a or the, and it also does not always need a number word like one.

So:

• thẻ can mean a card, the card, or cards, depending on context.

If you want to be more specific, you can add:

• một thẻ = one/a card
• những thẻ = cards
• cái thẻ đó = that card

But in a general statement such as They issue cards at the branch, just thẻ is completely normal.

Usually thẻ refers to a physical card or card-like item, such as:

• bank card
• ID card
• membership card
• access card

Examples:

• thẻ ngân hàng = bank card
• thẻ căn cước = identity card
• thẻ tín dụng = credit card

By itself, thẻ is fairly general, so the exact type usually comes from context.

Here, ở introduces the location where the action happens.

So:

• ở chi nhánh = at the branch

This is one of the most common uses of ở:

• ở nhà = at home
• ở trường = at school
• ở ngân hàng = at the bank

In this sentence, ở is not the main verb to be located/live. It is functioning more like a preposition: at / in.

Chi nhánh means branch, especially of a company, bank, or organization.

Examples:

• chi nhánh ngân hàng = bank branch
• chi nhánh công ty = company branch

So ở chi nhánh usually means:

• at the branch office
• at the local branch

If the context is banking, chi nhánh would very naturally mean bank branch.

The normal order here is:

Subject + Verb + Object + Location

So:

• Họ phát hành thẻ ở chi nhánh.

That is the most neutral word order.

You can move the location earlier for emphasis or topic-setting:

• Ở chi nhánh, họ phát hành thẻ.

This sounds like:

• At the branch, they issue cards.

It is grammatical, but the original sentence is more neutral and more common as a basic statement.

Vietnamese verbs do not change form for tense the way English verbs do.

So phát hành by itself does not mean specifically:

• issue
• issued
• will issue

The time is understood from context or from time words.

Without extra markers, Họ phát hành thẻ ở chi nhánh is often understood as:

• a present-time fact
• a habitual action
• a general statement

Depending on context, it could mean:

• They issue cards at the branch.
• They are issuing cards at the branch.
• They issued cards at the branch.
  if the surrounding conversation makes that clear

If you want to mark time more clearly, you can add words like:

• đã = past
• đang = ongoing
• sẽ = future

Examples:

• Họ đã phát hành thẻ ở chi nhánh. = They issued cards at the branch.
• Họ đang phát hành thẻ ở chi nhánh. = They are issuing cards at the branch.
• Họ sẽ phát hành thẻ ở chi nhánh. = They will issue cards at the branch.

In this sentence, the most natural meaning is at the branch.

That is because ở usually marks location, not destination.

So:

• ở chi nhánh = at the branch

If you wanted to say something more like to the branch, Vietnamese would more often use a different structure, depending on the exact meaning.

For example:

• đến chi nhánh = go to the branch
• cho chi nhánh = for the branch / to the branch

So in your sentence, the branch is the place where card issuance happens.

Yes, very often.

Vietnamese frequently omits subjects when they are obvious from context. So instead of saying:

• Họ phát hành thẻ ở chi nhánh.

a speaker might simply say:

• Phát hành thẻ ở chi nhánh.

This could mean:

• They issue cards at the branch
• We issue cards at the branch
• Cards are issued at the branch

The exact interpretation depends on context.

English usually requires a subject, but Vietnamese often does not.

It is mostly neutral.

• phát hành sounds a bit more official or administrative than a very casual everyday verb
• chi nhánh is also standard formal vocabulary for branch

So the sentence would fit well in:

• customer service
• banking
• official instructions
• business contexts

It is not overly stiff, but it does sound more institutional than casual conversation.

Tones matter a lot, because changing tones can change the word.

A rough breakdown:

• Họ — heavy falling tone
• phát hành — phát has a sharp rising tone; hành has a level tone
• thẻ — dipping/creaky tone
• ở — rising broken tone
• chi nhánh — chi level, nhánh rising tone

Even if your grammar is correct, wrong tones can make the sentence harder to understand.

A practical strategy:

1. Learn the sentence in chunks
2. Copy native audio
3. Focus on tones after you can say the words smoothly

Good chunks:

• Họ phát hành
• thẻ ở chi nhánh

Grammatically, maybe, but in natural English, issue cards is much better.

For administrative, banking, or service contexts:

• phát hành thẻ = issue cards

Using release cards would sound odd in English unless the context were something unusual, like a product launch. So even though phát hành can mean release in other contexts, here issue is the best choice.