There is no です because this sentence is in the plain style.
Also, 美しい is an i-adjective, and i-adjectives can end a sentence by themselves:
If you want to make it more polite, you can say:
Both are grammatical. The version without です sounds plain; the version with です sounds polite.
美しい is an i-adjective meaning beautiful.
In Japanese, i-adjectives can directly describe a noun or finish a sentence:
So in your sentence, 美しい is the predicate: it tells us what the cushion cover is like.
Yes, it is grammatical and understandable, but it may sound a little elevated, literary, or formal depending on context.
For everyday conversation, Japanese speakers might also use words like:
So:
Still, 美しい is absolutely correct.
The basic structure is:
So the overall pattern is:
A very literal gloss would be:
This topic-comment structure is extremely common in Japanese.
Using は presents this cushion cover as the topic and says something about it.
If you use が instead:
that can sound more like:
So は is more neutral for a simple description, while が often adds focus or contrast, depending on context.
No. Normally, Japanese is written without spaces:
The spaced version is often used in beginner materials to make the parts easier to read. In natural Japanese text, you would usually not see spaces like this.
Yes. Japanese adjectives can directly modify nouns.
So you can say:
But that is not exactly the same structure as the original sentence.
Compare:
このクッションカバーは美しい。
この美しいクッションカバー
The first is a full sentence. The second is just a noun phrase.
The easiest way is:
That keeps the meaning the same but makes the tone more polite.
You could also choose a more conversational adjective if appropriate, for example:
That may sound more natural in everyday speech, depending on what kind of beauty you want to express.