Dude wtf you're all over this site, are you John Lemmy or something?

Anyways, Japanese uses different writing systems – the first two that people usually learn (Kana) are basically just symbols for syllables (also called "mora"), Hiragana and Katakana. They use a different set of "letters" which represent the same sounds (you'll find a "ka", "m/n", "fu", "o", etc. in both, but they look different). There's also Kanji, which is an umbrella term for the various usages of characters which were adapted from Chinese, this includes Kana but generally people don't mean to include Kana when they say "Kanji". One Kanji can have MANY meanings and pronunciations, due to many multiple ways in which the character was adapted from Chinese, so the writing is extremely contextual. You can generally "spell out" a Kanji with Hiragana or Katakana, often times this is used when learning new Kanji or to disambiguate meaning. It's also one of the ways you use to type Japanese on a device/keyboard (the characters can be converted to a Kanji using software where you can pick based on a list of most common Kanji which are pronounced the way you typed).

Since Japanese doesn't use spaces or dots or anything usually, you'll often see all three mixed together in order to separate different words, although in modern times Katakana has especially been used for borrowings from foreign languages.

There's also Rōmaji, which is a term for the various romanization/latinization systems for Japanese. This one is also commonly used to type Japanese text.

The JLPT is the Japanese Language Proficiency Test, you take it to get a certificate stating your Japanese language abilities and the results are ranked from N5 being the lowest (correlates to ~A1-A2 CEFR, slightly more than beginner knowledge) to N1 being the highest (~B2-C2 CEFR, high level of abilities in the language)

The "alphabet" is generally the easiest part of learning a language, and an obviously important part, so the person being unwilling to put the time into it means he probably isn't serious enough about learning the language to actually follow it through.

Apologies if my explanation is off, I don't speak Japanese.