Furigana are hiragana characters used above 'Kanji' in yokogaki (horizontal writing) and on the right of 'Kanji' in tategaki (vertical writing) with smaller font, to show how each kanji is pronounced.
As to which kanji get furigana and which don't, it depends on the level of the writing, article, etc and their formality as well as difficulty for the intended readers.
There are a current list of 2136 standard use kanji, called 'Jouyou Kanji' that in Japanese newspapers don't need to get furigana, but anything out of that needs it as reading aid.
You can find furigana in texts inside educational books, depending on the level and newness of the kanji for the students. There are a specific margin assigned in formal application forms and such in Japan just in order to add furigana when necessary, such as multi-pronunciation names, since kanji usually have a different readings.
Katakana is something used rarely as furigana, you might only see it when there is a need to differentiate between On'yomi(Chinese reading of kanji, usually shown in katakana) and Kun'yomi (Japanese reading of kanji, usually shown in hiragana). That might just happen in linguistic books.
And as a reminder, since it happens a lot due to my experience, furigana is not to be mistaken with 'okurigana', which are part of a word not something out of it, the name is referred to the kana that are used along with kanji in a word, in order to complete it or inflect it grammatically. Take 悲, this is the kanji for 'grief, sadness'. But how to make an adjective, noun, verb etc out of it, and how to conjugate those would be the role of okurigana.
悲しい /ka na shii/ : sad
悲しみ /ka na shi mi/ : sadness
悲しむ /ka na shi mu/ : to sadden
hiragana katakana and kanji and furigana which is a mix of hiragana and katakana
Kana- there are 2 types, katakana and hiragana. Katakana is used for foreign loan words, foreign names, and it is used like italics. Hiragana is used for native Japanese words, and is used as furigana above kanji, the Chinese characters in Japanese. Furigana is just the pronunciation of the Kanji.
紅玉 (kou gyo ku) is Japanese for 'ruby'. They also use the borrowed word ルビー (ru bii) for the same word. But if you mean what does Japanese linguistic term 'ruby' mean, it is the general term used to refer to 'furigana' and 'furikanji', each of which appear next to the other to explain pronunciation of it, like you see in Japanese newspapers, above the kanji letters there are hiragana characters to explain its reading, and sometimes vice versa.
Japanese is written in five scripts: kanji, hiragana, katakana, romanji, and furigana. Each script serves a different purpose in the written language.
You can read or download the Bible in over 100 languages online at related links. You can also listen to or download the audio at the same place. See attached link.
Kyotsugo is a Japanese term for adding furigana, which are tiny kana characters written above or next to kanji characters to show their pronunciation. This helps readers, especially children or those learning the language, to know how to pronounce unfamiliar kanji characters.
Deniva does not mean anything in Japanese.
Didi does not mean anything in Japanese.
"Olga" is not a Japanese word or name, so it doesn't mean anything at all in Japanese. Did you mean, "What is the name "Olga" translated to in Japanese?"
The name 'Collin' does not mean anything in Japanese, but it can be written in Japanese as: コリン
Kaitlyn does not mean anything in Japanese, but can be written in Japanese as: ケイトリン
This does not mean anything in Japanese.