Translation:This bag is heavy.
鞄（かばん） is a word that is written in katakana for informal and casual usage. This is mostly historically because カバン is a loan word from China very long ago. Odds are, you'd either see it written in kanji (for most occasions, especially formally) or katakana. I'd suspect you're most common to see it in hiragana when used as furigana for the kanji.