I wrote it in hiragana as じよん which I checked online and more than one place spelled it the same way as I did. I am using the exact same letters as katakana only in hiragana. So why does DuoLingo say this is wrong??? Ok minutes later now...I didn't use the small よ ....I think that was the problem... :)
I'd kindly recommend reading through the comments first, has been answered numerous times already: https://forum.duolingo.com/comment/23297544?comment_id=40853750
Yup, it's フィンランド (Finrando).
There's also an Ateji (phonetic) reading Kanji 芬蘭, however most countries will always be written in Katakana rather than Kanji. Even though there are Kanji for some countries, since Katakana was introduced, it's easier to spell out foreign words in Japanese.
Today only Japan（日本）
DPRK (North Korea)（北朝鮮/朝鮮民主主義人民共和国）
are officially written with Kanji in Japanese.
Also you were wondering about your name (?) [though I think you deleted that comment] ; it's マティルダ (Matiruda).
Probably explained a dozen times in the comments already, but here we go again :D
Typing "jo" while using Japanese input should already result in the suggested Kana「じょ」＆「ジョ」. If it doesn't for you, try entering "x" before the Kana you want to write the small version of. In this case type "jixyo".
By the way, I'm using SwiftKey on Android.
Not sure if not all comments were loaded in when you posted that question or you didn't read before posting, but I wrote what I use literally above your post :D
Anyway, I use SwiftKey for Android (like I said here: https://forum.duolingo.com/comment/23297544?comment_id=40853750)
See my explanation here: https://forum.duolingo.com/comment/23297544?comment_id=40853750
The small kana combines with and modifies the one before it. You can type it by writing the pronunciation of the new sound. "Jo" or "Jyo" ジョ (one syllable) instead of "Ji Yo" ジヨ (two syllables)
You can also make a kana small by itself by adding an "x" or "l" before it. "xyo" or "lyo" ョ