Prisafslaget står i emailen.

Because -et makes the noun definite.

• et prisafslag = a price reduction / a discount
• prisafslaget = the price reduction / the discount

In this sentence, it is a specific discount that both speaker and listener know about, so Danish uses the definite form.

Literally, yes: står is the present tense of stå, which usually means to stand.

But in Danish, stå is also often used the way English uses say, be written, or appear when talking about text. So:

• Det står i emailen = It says so in the email
• more literally: It stands in the email

This is a very common Danish way to talk about written information.

Because Danish often prefers stå for information that is written somewhere.

Compare:

• Det er i emailen = It is in the email
  
  • grammatically possible, but more neutral and less idiomatic if you mean written information
• Det står i emailen = It says so in the email / It is written in the email
  
  • this is the natural choice here

So står tells you that the discount is mentioned in the text of the email.

I usually means in.

So:

• i emailen = in the email

Danish uses i very naturally for written documents, messages, emails, letters, books, and similar things when something is contained in the text.

Examples:

• Det står i brevet = It says so in the letter
• Det står i bogen = It says so in the book

All of these forms may be seen, depending on style and spelling preference:

• emailen
• e-mailen
• mailen

In modern everyday Danish, mailen and emailen are both common. The sentence you were given uses emailen, which is perfectly understandable.

The ending -en shows that email is treated as a common gender noun:

• en email
• emailen

You mostly have to learn the gender of each noun, just as you would in many other European languages.

Here it is:

• en email
• emailen

That tells you it is a common gender noun, not a neuter noun.

The basic structure is:

• Prisafslaget = subject
• står = verb
• i emailen = prepositional phrase

So the sentence follows normal Danish main-clause word order:

Subject + verb + other information

This is very similar to English:

• The discount is in the email
• The discount is mentioned in the email

Yes, it is grammatically possible, but it usually sounds less natural if you mean that the discount is written/mentioned there.

• Prisafslaget står i emailen = The discount is stated in the email
• Prisafslaget er i emailen = The discount is in the email

The second version focuses more on location; the first is more idiomatic for written information.

Yes. Danish very often forms one long noun where English uses several words.

So:

• pris = price
• afslag = reduction / deduction / discount
• prisafslag = price reduction / discount

This is completely normal in Danish. English often writes these as separate words, but Danish usually combines them.

A rough English-friendly approximation is:

PREES-af-slah-et staw-er ee ee-mail-en

A few notes:

• pris sounds roughly like prees
• afslag has a soft Danish g at the end, which may be very weak or almost disappear in speech
• står has the Danish å, something like the vowel in British law
• i is like ee
• emailen is usually stressed early: E-mailen

Exact pronunciation depends on accent and speaking speed.

Yes, but they are not always used in exactly the same way.

• rabat is the everyday word for discount
• prisafslag often sounds a bit more formal or specific, like a price reduction

So in a business or customer-service context, prisafslag can sound very natural. In casual shopping situations, rabat is often more common.

Example:

• Jeg fik rabat = I got a discount
• Vi gav et prisafslag = We gave a price reduction

Yes, especially if the intended meaning is The discount is mentioned/stated in the email.

If you want to be very literal about physical or textual location, Danish may still use this sentence naturally, because står i emailen strongly suggests that the information appears in the email text.

So this is a good, natural Danish sentence.