Biểu mẫu này thiếu chữ ký.

A natural word-by-word breakdown is:

• biểu mẫu = form, document form, template-style official form
• này = this
• thiếu = to lack, to be missing
• chữ ký = signature

So the whole sentence means:

This form is missing a signature
or
This form lacks a signature

A very literal structure would be:

form this lacks signature

That is normal Vietnamese word order.

In Vietnamese, demonstratives like này (this) usually come after the noun.

So:

• biểu mẫu này = this form
• người này = this person
• cuốn sách này = this book

This is one of the first word-order differences English speakers notice. English says this form, but Vietnamese says form this.

Biểu mẫu is a fairly formal or administrative word for a form, especially a standardized document used for filling in information.

Depending on context, Vietnamese might also use:

• mẫu đơn = application form / form
• đơn = application, petition, form
• form = the English loanword, common in casual speech or office contexts

So biểu mẫu is correct and natural, especially in official or written contexts. It sounds a bit more formal than everyday speech in some situations.

Thiếu means to lack, to be short of, or to be missing.

In this sentence:

• Biểu mẫu này thiếu chữ ký = This form lacks a signature / is missing a signature.

A useful pattern is:

[something] + thiếu + [what is missing]

Examples:

• Hồ sơ này thiếu ảnh. = This application file is missing a photo.
• Đơn này thiếu ngày tháng. = This form is missing the date.
• Tôi thiếu tiền. = I don’t have enough money / I’m short of money.

So thiếu can describe missing information, missing items, or insufficient amounts.

Chữ ký means signature.

It is made of:

• chữ = writing, letters, script, word-like written characters
• ký = to sign

Historically or literally, it has the sense of a written sign/name mark, but in modern Vietnamese, you should simply learn chữ ký as the normal word for signature.

Examples:

• ký tên = to sign one’s name
• chữ ký của bạn = your signature
• thiếu chữ ký = missing a signature

Vietnamese does not use articles like English a/an/the.

So chữ ký can mean:

• a signature
• the signature
• signature in a general sense

The exact meaning depends on context.

In Biểu mẫu này thiếu chữ ký, English naturally says a signature, but Vietnamese does not need a separate word for a.

That is completely normal.

Both are possible in Vietnamese, but biểu mẫu này is perfectly normal.

Classifiers such as cái, tờ, or cuốn are often used in Vietnamese, but they are not always required, especially in formal writing or when the noun itself is clear enough.

For example:

• biểu mẫu này = this form
• cái biểu mẫu này = this form

The version with cái can sound more conversational or emphatic in some contexts, but the version without it is very natural, especially in formal or written language.

You might also hear:

• tờ biểu mẫu này

But in your sentence, Biểu mẫu này is completely fine.

It sounds neutral to formal.

Reasons:

• biểu mẫu is somewhat formal or administrative
• the sentence is short and matter-of-fact
• it sounds like something you might see in an office, on a notice, or from staff reviewing documents

In casual speech, someone might say:

• Form này thiếu chữ ký.
• Mẫu này chưa có chữ ký.
• Tờ này chưa ký.
  This last one can mean This document hasn’t been signed yet, depending on context.

So your original sentence is natural and especially suitable in official or workplace settings.

Yes, you could say that.

• Biểu mẫu này thiếu chữ ký = This form is missing a signature / lacks a signature.
• Biểu mẫu này không có chữ ký = This form does not have a signature.

The difference is small, but:

• thiếu often suggests that something should be there but is absent
• không có simply states that it is not there

So if you are checking paperwork and a signature is required, thiếu chữ ký is especially natural because it implies something is incomplete.

You can say:

• Biểu mẫu này thiếu chữ ký của bạn.

Breakdown:

• chữ ký = signature
• của bạn = your

So:

• chữ ký của bạn = your signature

This is a very common pattern:

noun + của + person

Examples:

• tên của tôi = my name
• số điện thoại của anh ấy = his phone number
• chữ ký của bạn = your signature

A rough pronunciation guide is:

• Biểu — rising-dipping kind of contour
• mẫu — heavy falling/glottalized tone
• này — level tone
• thiếu — rising tone
• chữ — heavy falling/glottalized tone
• ký — high rising tone

A rough English-style approximation is:

Bee-uhw maww nigh thyee-oo chuh kee

But this is only approximate. The tones matter a lot.

A more useful learner tip is to practice in chunks:

• biểu mẫu này
• thiếu chữ ký

Then combine them:

Biểu mẫu này / thiếu chữ ký.

If you want to sound natural, make sure thiếu chữ ký flows smoothly as one unit.

Yes, thiếu is used very broadly.

It can be used for:

1. Missing parts of documents

   • Đơn này thiếu chữ ký. = This form is missing a signature.

2. Lacking physical things

   • Nhà bếp thiếu muối. = The kitchen is out of salt.

3. Not enough of something

   • Tôi thiếu thời gian. = I’m short of time.
   • Công ty thiếu nhân viên. = The company lacks staff.

So thiếu is a very useful word and not limited to paperwork.

A simple yes/no question would be:

• Biểu mẫu này thiếu chữ ký à?
• Biểu mẫu này thiếu chữ ký phải không?

These mean:

• Is this form missing a signature?

The two endings have slightly different feelings:

• à = simple spoken yes/no question
• phải không = right? / is that correct?

You could also ask more directly:

• Biểu mẫu này thiếu chữ ký của ai? = Whose signature is missing on this form?
• Biểu mẫu này thiếu gì? = What is missing from this form?

These are very practical patterns for real-life use.