Indsigelsesblanketten skal udfyldes.

It is a compound noun made of:

• indsigelse = objection
• blanket = form
• -en = the definite ending

So the core noun is blanket, and the whole word means the objection form.

Danish very often joins nouns into one long word, where English would often use several words.

That -s- is a very common linking element in Danish compounds.

So:

• indsigelse
  • blanket
    becomes
• indsigelsesblanket

It does not usually need to be translated separately. You can think of it as a natural connector between the two parts of the compound. English sometimes does something similar with claims form, drivers license, etc., but Danish uses one written word much more often.

In Danish, the definite article is usually attached to the end of the noun.

So:

• en blanket = a form
• blanketten = the form

That is why you get indsigelsesblanketten rather than a separate word before the noun.

Because blanket is a common gender noun in Danish.

For common gender nouns:

• indefinite singular: en blanket
• definite singular: blanketten

If it were a neuter noun, you would normally see -et instead.

Here skal expresses obligation or requirement.

In this kind of official sentence, it usually means something like:

• must
• has to
• sometimes is to

So this is not just a suggestion. It sounds like a formal instruction or requirement.

Because skal is a modal verb, and modal verbs in Danish are followed by the bare infinitive.

For example:

• skal udfylde
• kan komme
• vil vente

So after skal, you do not use at.

Udfyldes is the passive infinitive of udfylde in the -s passive.

Compare:

• at udfylde = to fill in / to complete
• at udfyldes = to be filled in / to be completed

In this sentence:

• Indsigelsesblanketten skal udfyldes = The objection form must be filled in

So the form is the thing receiving the action, not doing it.

Danish has two common ways to make the passive:

1. -s passive

   • udfyldes

2. blive + past participle

   • blive udfyldt

Both can often be translated with English be + past participle, but they are used a bit differently.

In formal instructions, notices, rules, and administrative language, the -s passive is very common and sounds natural:

• Blanketten skal udfyldes

Using blive udfyldt is also possible in some contexts, but udfyldes is especially typical in official written Danish.

An active version would name the person who must do the action, for example:

• Du skal udfylde indsigelsesblanketten.
• You must fill in the objection form.

So:

• active: someone fills in the form
• passive: the form must be filled in

The passive is useful when the doer is unimportant, unknown, or obvious from context.

The sentence follows normal Danish main-clause word order:

• Indsigelsesblanketten = subject
• skal = finite verb
• udfyldes = infinitive/passive verb

So the pattern is:

• subject + finite verb + other verb material

This also matches the Danish V2 rule: in a main clause, the finite verb normally comes in the second position.

For example:

• Indsigelsesblanketten skal udfyldes.
• I dag skal indsigelsesblanketten udfyldes.

In both cases, the finite verb skal stays in second position.

Yes, very often.

Udfylde is the standard verb for filling in or completing a form, application, questionnaire, and similar documents.

Examples:

• udfylde en blanket = fill in a form
• udfylde en ansøgning = fill in an application
• udfylde et skema = fill in a form/questionnaire

So in administrative Danish, udfylde is exactly the word you expect here.

Yes. It sounds formal, administrative, and typical of official documents.

That is because of things like:

• the long compound noun indsigelsesblanketten
• the passive construction skal udfyldes

A more direct everyday version might be:

• Du skal udfylde indsigelsesblanketten.

But on forms, websites, letters, and official instructions, Indsigelsesblanketten skal udfyldes sounds very normal.