I write (with a) pen.
How would i write the 3 statements? 1. I write pen. 2. I write with a pen. 3. I write on a pen.
Is the following correct? 1. ペンを書く 2. ペンで書く 3. ペンに書く
I am a native speaker of Japanese and I have a different opinion. All three answers you wrote were correct!!! If you want to say I write a word "pen", then it is completely ok to say ペンを書く. It is not a typo. Although ペンと書く is more natural way of saying. And if you want to say I draw a picture of pen, then you have to use the kanji 描く. The pronunciation is same as かく, but it means "draw". In this case, you cannot say ペンと描く。because it sounds awkward.. ペンを書く and ペンで書く is completely different. Although sometimes you may see it is used as same meaning, I don't think it is grammatically correct. The latter means write with a pen, as you answered correctly.
So in conclusion, here is a suggestion:
I write a word "pen". ペンを書く。ペンと書く。
I draw a picture of pen. ペンを描く。
I write with a pen. ペンで書く。ペンを使って書く。
I write on a pen. ペンに書く。ペンの上に書く。
ペンを描く (ぺんをかく) means I draw a pen. Same sound, different verb.
ペンで書く means I write with a pen.
ぺんで描く means I draw with a pen.
ぺんに書く means I write inside a pen. Either the pen would have to be very large, or you would have to be very small. You would likely clarify that you were writing on a pen by being more exact, like ぺんの上にかきます。this would be confusing unless you were having a conversation about writing on pens.
You would likely use parenthesis or something to clarify you were writing “pen” so as not to confuse the user, who is already baffled by a foreigner speaking Japanese.
It means "typo" in Japanese.
You can use that structure when you are writing something, like a message or a love letter. But it doesn't sound right when you use it to "write" an object that cannot be written or to describe writing a specific word.
1) 手紙を書く "I write a letter"
2) ペンを書く "I write a pen"
Since you cannot write a pen, the second sentence doesn't work. You could make a drawing of a pen (using a different verb) or write the word "pen" (using the quoting structure supplied by Arachnje), but you can't write a pen.
Actually, my first thought was that ペンを書く was not correct, but then I did a search with the sentence in quotations, and it seems to be used in a way similar to ペンで書く(see the title of this picture and note also the English sentence in the link address) .
P.S. "typo" in Japanese is 書き間違え ，打ち間違え, or ミスタイプ