Han skulle ha antecknat allt på papper i stället för på mobilen.

It is the pattern skulle + ha + supine and refers to a past action seen as unreal, expected, or preferable in hindsight.

In English, this kind of Swedish structure is often translated as:

• would have written down
• sometimes should have written down, depending on context

So the construction is not just simple past. It points to something that was not done the way the speaker thinks it should, would, or was supposed to be done.

Because after ha, Swedish normally uses the supine form.

Here are the forms:

• anteckna = infinitive, to note down
• antecknade = simple past, noted down
• antecknat = supine, used after ha

So:

• Han antecknade allt = He noted everything down
• Han har antecknat allt = He has noted everything down
• Han skulle ha antecknat allt = He would/should have noted everything down

Even though antecknat can look like a participle form, here it is functioning as part of the verb phrase after ha.

Not exactly.

• borde ha is the clearest way to say should have
• skulle ha often has a broader meaning: would have, was supposed to, or something like should have depending on context

So:

• Han borde ha antecknat allt = more direct advice or criticism
• Han skulle ha antecknat allt = can sound more like an expectation, plan, or hindsight judgment

In real usage, there can be overlap, which is why context matters a lot.

Because allt means everything or all of it, while alla means all with plural nouns or everyone.

Compare:

• allt = everything
• alla böcker = all books
• alla = everyone / all of them

So antecknat allt means written everything down.

Because på papper is an idiomatic general expression meaning on paper, in writing, or using paper rather than a digital device.

It does not mean one specific sheet of paper. It refers to the medium in a general way.

Compare:

• på papper = on paper, in hard copy, in writing
• på ett papper = on a piece of paper
• på pappret = on the paper / on that specific paper

So in this sentence, på papper is the natural general expression.

Because both parts need the same preposition.

The sentence is contrasting two different places or media:

• på papper
• på mobilen

After i stället för, Swedish often repeats the preposition to keep the structure clear and natural.

So:

• på papper i stället för på mobilen = on paper instead of on the phone

This is very normal Swedish.

I stället för means instead of.

Useful comparison:

• i stället = instead
• i stället för = instead of

Examples:

• Jag tog te i stället. = I had tea instead.
• Jag tog te i stället för kaffe. = I had tea instead of coffee.

Both spellings i stället and istället are accepted, so you may also see istället för.

Because på mobilen is the most natural general way to talk about doing something on a phone, especially with screens, typing, reading, storing notes, or using apps.

Examples:

• Jag läste det på mobilen.
• Hon skrev det på mobilen.

I mobilen can sometimes be used when you want to emphasize that something is inside the phone, such as in its memory or in an app, but in everyday Swedish på mobilen is usually the idiomatic choice here.

Because Swedish often uses the definite form when the ownership is obvious from context.

So på mobilen can naturally mean:

• on the phone
• on his phone

If you want to make the ownership explicit, you can say:

• på sin mobil = on his own phone

That version is also correct, but it is not always necessary. The shorter på mobilen sounds natural when everyone already understands whose phone is meant.

They are close, but not always identical.

• anteckna = to note down, to take notes
• skriva ner = to write down

Anteckna often suggests making notes in a more deliberate or organized way, while skriva ner is broader and more everyday.

Compare:

• Hon antecknade allt läraren sa. = She took notes on everything the teacher said.
• Skriv ner numret. = Write the number down.

In this sentence, antecknat fits well because it is about noting information down.