Hãy giữ hóa đơn.

Hãy is a particle used to form a polite or neutral command / request, similar to please or do in English commands.

So in Hãy giữ hóa đơn, hãy signals that the speaker is telling someone to do something.

A few notes:

• It is common in written instructions, announcements, reminders, and formal speech.
• It can sound a bit more deliberate or official than a plain verb alone.
• It does not mean exactly the same thing as English please in every context, but it often plays a similar role in softening or framing a command.

Yes. You can say:

• Giữ hóa đơn.

This is still grammatical and often sounds more direct, like an instruction on a sign, label, or spoken command.

The difference is roughly:

• Hãy giữ hóa đơn. = a more explicit imperative, often a little more formal or instructional
• Giữ hóa đơn. = shorter, more direct

In real-life Vietnamese, especially in conversation, speakers often use other patterns instead of hãy, such as:

• Nhớ giữ hóa đơn nhé. = Remember to keep the receipt, okay?
• Giữ lại hóa đơn nhé. = Keep the receipt, okay?

Vietnamese often leaves out the subject when it is obvious from context, especially in commands.

English usually needs you only sometimes in commands:

• Keep the receipt.

Vietnamese works similarly:

• Hãy giữ hóa đơn.

The person being addressed is understood from the situation, so no pronoun is necessary.

If you wanted to add one, you could, but it depends on who you are talking to:

• Anh hãy giữ hóa đơn.
• Chị hãy giữ hóa đơn.
• Các bạn hãy giữ hóa đơn.

Because Vietnamese pronouns depend heavily on age, relationship, and social context, leaving them out is often the easiest and most natural choice in short instructions.

Giữ is a common verb meaning to keep, to hold, to retain, or to preserve, depending on context.

In this sentence, it means keep in the sense of do not throw away / keep it with you.

Examples of giữ in other contexts:

• giữ chỗ = reserve a seat / save a place
• giữ im lặng = keep silent
• giữ tiền = keep the money
• giữ gìn sức khỏe = take care of one’s health

So here, giữ hóa đơn means keeping the receipt rather than discarding it.

Hóa đơn commonly refers to a bill, invoice, or receipt, depending on context.

That is why learners sometimes get confused. In practice:

• in a shop or customer-service context, hóa đơn can mean the paper record of the purchase, often translated as receipt
• in business contexts, it may be closer to invoice
• in restaurant or payment contexts, it may mean bill

So the best English translation depends on the situation, not just the dictionary meaning.

Related word:

• biên lai often means a receipt or proof of payment in a more official or administrative sense

Vietnamese word order here is straightforward:

• hãy = imperative marker
• giữ = verb
• hóa đơn = object

So the pattern is:

imperative marker + verb + object

This is very natural Vietnamese word order. It matches the basic logic of:

• tell someone to do something
• state the action
• then state what the action applies to

Yes, slightly.

• giữ hóa đơn = keep the receipt
• giữ lại hóa đơn = keep the receipt / keep it back / hold on to it

The added word lại often gives the sense of retaining something instead of getting rid of it. In many real situations, giữ lại hóa đơn sounds very natural because it clearly suggests don’t throw it away.

So:

• Hãy giữ hóa đơn. = correct and natural
• Hãy giữ lại hóa đơn. = also very natural, often with a stronger sense of hold onto it

It is grammatical and natural, but it leans a bit toward instructional or formal-neutral language because of hãy.

You might see or hear it in:

• written instructions
• customer notices
• reminders
• official speech

In everyday conversation, speakers often prefer softer or more conversational forms, such as:

• Nhớ giữ hóa đơn nhé.
• Giữ hóa đơn lại nhé.
• Anh/chị nhớ giữ hóa đơn.

These often sound warmer and more natural in person.

So Hãy giữ hóa đơn is fine, but not always the most conversational choice.

A rough pronunciation guide for English speakers is:

• Hãy ≈ high with a broken, dipping-rising tone
• giữ ≈ roughly zyoo or yuh depending on dialect, with a heavy tone
• hóa ≈ hwah with a rising tone
• đơn ≈ duhn with a level tone

A few useful pronunciation points:

• gi in northern Vietnamese often sounds like z; in southern Vietnamese it may sound closer to y
• đ is not the same as d in English; it is a normal d-like sound, while Vietnamese d is pronounced differently
• tones are very important, so even if the consonants are close, the tones help distinguish the words

Yes, but it changes the meaning slightly.

• Hãy giữ hóa đơn. = Keep the receipt.
• Hãy giữ hóa đơn này. = Keep this receipt.

Adding này makes the receipt more specific: it means this one.

If the context already makes it obvious which receipt is meant, Vietnamese often leaves này out. That is why the shorter sentence sounds perfectly natural.