Japanese does not have a single alphabet like English. Instead it uses three writing systems together, hiragana, katakana and kanji, each with its own job, plus rōmaji, the Latin-letter transcription used to help learners. It looks daunting at first, but the system is logical, and beginners usually start with hiragana.
This guide explains the Japanese alphabet, what each script is for, and includes the full hiragana and katakana charts with their rōmaji readings.