La federa del cuscino va cambiata ogni settimana.

Federa means pillowcase: the removable fabric cover that goes over a pillow.

So in this sentence:

• la federa = the pillowcase
• il cuscino = the pillow

A federa is not the pillow itself.

Del is the contraction of di + il:

• di = of
• il = the
• di + il = del

So:

• la federa del cuscino = the pillow’s pillowcase / the pillowcase of the pillow

In natural English we usually just say the pillowcase, but Italian often keeps the relationship more explicit.

Here va cambiata means needs to be changed, should be changed, or is to be changed.

Literally, andare + past participle can look strange to English speakers, because va normally means goes. But in this structure, it does not mean physical movement.

So:

• va cambiata = needs changing / should be changed

This is a very common Italian pattern:

• va fatto = it needs to be done
• va detto = it should be said
• va pulita = it needs to be cleaned

Because cambiata agrees with la federa, which is feminine singular.

• federa = feminine singular
• so the past participle must also be feminine singular: cambiata

Compare:

• Il cuscino va cambiato = The pillow needs to be changed
• La federa va cambiata = The pillowcase needs to be changed

The ending changes to match the noun.

Yes, it is very close to a passive idea.

La federa del cuscino va cambiata focuses on the thing receiving the action, not the person doing it. In English, the most natural translations are:

• The pillowcase should be changed every week
• The pillowcase needs to be changed every week

So it is not a basic active sentence like Someone changes the pillowcase every week. It presents the pillowcase as the thing that must undergo the action.

Yes. That is absolutely correct.

Compare the two:

• La federa del cuscino va cambiata ogni settimana
• La federa del cuscino deve essere cambiata ogni settimana

Both mean roughly the same thing: the pillowcase should/needs to be changed every week.

The difference is mostly in style:

• va cambiata is very natural and compact
• deve essere cambiata is a little more explicit and formal-sounding

Both are common.

Yes, and that is also very natural.

It means:

• One must change the pillowcase every week
• You need to change the pillowcase every week

The difference is in focus:

• La federa del cuscino va cambiata... focuses on the pillowcase
• Bisogna cambiare la federa del cuscino... focuses more on the necessary action

Both are good Italian.

Italian usually uses articles more often than English.

So la federa del cuscino is perfectly normal, even where English might use a more general statement like:

• Pillowcases should be changed every week

Italian often prefers:

• La federa del cuscino va cambiata ogni settimana

This can sound general even though it uses the singular with the definite article.

Italian often uses the singular definite article to talk about something in general.

The correct form is ogni settimana.

A few useful points:

• ogni means every
• after ogni, you normally use a singular noun
• you do not use an article after ogni

So:

• ogni settimana = every week
• ogni giorno = every day
• ogni mese = every month

Not:

• ogni le settimane
• ogni la settimana

Yes. Italian word order is flexible.

The original sentence:

• La federa del cuscino va cambiata ogni settimana

You could also say:

• Ogni settimana la federa del cuscino va cambiata
• La federa del cuscino ogni settimana va cambiata

The first version is the most neutral and natural. Moving ogni settimana to the front gives it a bit more emphasis, like Every week, the pillowcase should be changed.

It can mean either, depending on context, but here it clearly means pillow.

Why? Because federa is a pillowcase, so la federa del cuscino strongly suggests a bed pillow.

In other contexts, cuscino can also mean cushion. Italian sometimes relies on context more than English does.

Usually, it is understood as a general recommendation: pillowcases should be changed every week.

Even though it uses the singular:

• la federa del cuscino

Italian often uses the singular definite form to express a general truth or habit.

So this sentence can mean something like:

• The pillowcase should be changed every week
• A pillowcase should be changed every week
• Pillowcases should be changed every week

The exact English wording depends on style, but the Italian is perfectly natural as a general statement.