Hun går på videregående skole.

In this sentence, gå på is an idiomatic expression meaning to attend a school or course.

So Hun går på videregående skole means she attends high school or she is in high school, not that she is physically walking anywhere.

This pattern is very common:

• Hun går på skole. = She goes to school / attends school.
• Han går på universitetet. = He attends university.

So here, går keeps its usual form, but the whole expression går på has a special meaning.

With schools and many other institutions, Norwegian often uses på in the sense of attending.

So:

• gå på skole
• gå på universitetet
• gå på kurs

This is just the normal Norwegian pattern and does not translate word-for-word into natural English.

Compare:

• Hun går til skolen. = She walks/goes to the school (physical movement toward it)
• Hun går på skolen. = She attends the school / she is at the school
• Hun går på videregående skole. = She attends high school

So på is the right preposition for the idea of being enrolled in or attending school.

Norwegian often leaves out the article in fixed expressions about school, work, church, and similar institutions when the meaning is institutional rather than a specific building.

So:

• gå på skole = attend school
• gå på videregående skole = attend high school

This is similar to English expressions like go to school, where English also leaves out the article.

If you want to talk about a specific school as a countable noun, you can use an article:

• Hun går på en videregående skole i Bergen. = She attends a high school in Bergen.

So in your sentence, the article is omitted because the phrase is talking about the type of schooling, not highlighting one particular school building.

Videregående skole is the Norwegian term for upper secondary school, often translated as high school.

The parts are:

• videregående = continuing / further / advanced
• skole = school

So the phrase refers to the school level after lower secondary school.

In everyday English explanations for learners, high school is usually the easiest translation, even though school systems do not match perfectly from country to country.

Videregående behaves like an adjective here, describing skole.

Many Norwegian adjectives ending in -ende or -gående do not change form very much. So videregående stays the same here.

That means you do not need to worry about changing it to match gender in this phrase.

Examples:

• en videregående skole
• på videregående skole

The form videregående is the standard one you learn as part of the fixed expression.

Går is the present tense of å gå.

The basic forms are:

• å gå = to go
• går = go / goes / am going / is going
• gikk = went
• har gått = have/has gone

So Hun går på videregående skole is in the present tense: she goes to / attends high school.

Yes. Very often, especially in everyday speech, Norwegians shorten this to:

• Hun går på videregående.

That still means she is in high school.

Including skole sounds a bit fuller or more explicit, but both are correct.

The difference is mainly between attending and being physically there.

• Hun går på videregående skole. = She attends high school.
• Hun er på videregående skole. = She is at the high school.

So går på usually refers to her status as a student, while er på more naturally refers to location.

In some contexts, er på videregående can also mean is in high school, but går på videregående is the clearest and most standard way to say someone attends that school level.

This is normal Norwegian main-clause word order:

• Hun = subject
• går = verb
• på videregående skole = prepositional phrase

So the basic structure is:

Subject + verb + the rest

Norwegian also follows the V2 rule, which means the finite verb is usually in the second position in main clauses.

For example:

• Hun går på videregående skole.
• Nå går hun på videregående skole.

In the second sentence, Nå comes first, so the verb går still stays in second position, and the subject moves after it.

Yes, but it changes the meaning slightly.

• Hun går på videregående skole. = She attends high school.
  This is the general, institutional meaning.

• Hun går på den videregående skolen. = She attends that specific high school.
  This points to a particular school.

• Hun er på skolen. = She is at the school.
  This is often about location.

So the version without a definite ending sounds more general and is the usual way to talk about being in high school.

Hun is the third-person singular feminine subject pronoun, meaning she.

So:

• hun = she
• henne = her

In your sentence, hun is the subject, so hun is the correct form:

• Hun går på videregående skole.

You would not use henne here, because henne is an object form.