Thẻ thư viện này có mã vạch.

In Vietnamese, demonstratives such as này usually come after the noun phrase, not before it.

So:

• thẻ thư viện này = this library card
• literally: library card this

That is normal Vietnamese word order.

A useful pattern is:

• noun + này = this noun
• noun + kia / đó = that noun

Because thư viện modifies thẻ, the whole noun phrase is thẻ thư viện, and then này goes after the whole thing:

• thẻ thư viện này = this library card

Here, có means to have.

So có mã vạch means has a barcode.

In Vietnamese, có is very common and can mean different things depending on context, but in this sentence it is the ordinary possession verb:

• Tôi có sách. = I have a book / books.
• Thẻ thư viện này có mã vạch. = This library card has a barcode.

It is not a form of to be. Vietnamese often uses có where English would use has.

Vietnamese noun phrases often put the main noun first, followed by a word that describes or narrows it.

Here:

• thẻ = card
• thư viện = library

So:

• thẻ thư viện = library card
  literally something like card library

The head noun is thẻ, and thư viện tells you what kind of card it is.

This pattern is very common in Vietnamese:

• xe buýt = bus
• nhà bếp = kitchen
• học sinh = student

So even though the order feels reversed from English, it is normal Vietnamese structure.

Vietnamese often does not use an equivalent of English a/an unless it is needed.

So:

• có mã vạch naturally means has a barcode

If you said:

• có một mã vạch

that would mean has one barcode or has a barcode, but it sounds a bit more specific or counted.

In many everyday sentences, Vietnamese leaves out một unless the number one matters or the speaker wants to be more explicit.

So the version without một is very natural.

Mã vạch is a fixed expression meaning barcode.

Individually:

• mã = code
• vạch = line / stripe

Together, they form the standard Vietnamese term for barcode.

So learners should treat mã vạch as one vocabulary item, even though it is written as two words.

Yes, you could say:

• Cái thẻ thư viện này có mã vạch.

This is grammatical. The classifier cái can be used with many inanimate objects, including cards.

However, in many contexts, especially when the noun is already clear, Vietnamese often leaves the classifier out. So:

• Thẻ thư viện này có mã vạch.

sounds perfectly natural.

Very roughly:

• thẻ thư viện này = this library card
• cái thẻ thư viện này = this library card, with a slightly fuller noun phrase

Not every sentence needs a classifier.

Yes. If you remove này, the sentence becomes:

• Thẻ thư viện có mã vạch.

That means something like:

• The library card has a barcode
• Library cards have barcodes
• A library card has a barcode

The exact interpretation depends on context.

Adding này makes it specifically this library card. Without này, the sentence is more general or less specific.

A careful approximation is:

• Thẻ thư viện này có mã vạch.
• roughly: teh thuh vee-en nai kaw ma vahk

A few notes:

• thẻ has the hỏi tone
• thư has the level tone
• viện has the nặng tone
• này has the huyền tone
• có has the sắc tone
• mã has the ngã tone
• vạch has the nặng tone

A learner should especially watch:

• th in thẻ: an aspirated t sound, not English th
• ư in thư: a vowel that does not exist in English
• final -ch in vạch: short and unreleased

If you want to sound natural, it helps to learn the whole sentence rhythm rather than only each word separately.

Yes. It is a completely natural Vietnamese sentence.

Structure:

• Thẻ thư viện này = subject
• có = verb
• mã vạch = object

So it is a straightforward statement meaning that this particular library card has a barcode.

Vietnamese often allows very compact sentences like this without articles, extra linking verbs, or plural marking. That is one reason it may look shorter than the English equivalent.