If you said it in an angry way I would probably be offended. If you said it in a joking way I would probably laugh and agree (if we knew each other). "klutz" is one of those words that you can use without giving offence, if you're talking to a friend.

It is not a nice thing to call someone, though it could be a term of affection between people who know each other well. On the other hand, there are far more offensive things you could call someone in English! I would recommend caution.

It's one of those words that can be offensive or not offensive depending on context. If you said it to me jokingly, as a friend, then I wouldn't mind, but if a stranger said it to me or if someone said it angrily, I would.

Thank you,for your reply.

Yes. https://dictionary.cambridge.org/dictionary/english/klutz https://www.urbandictionary.com/define.php?term=Klutz