Moving to Japan, Hanko needed

Hello everyone ! I am moving to Japan soon and I need a Hanko.

I would like to make it official, so I hear I need to use my full name, which, as I am French, is 3 surnames and a last name.... Do you know if it is correct because the Hanko is going to be a full mess.

Moreover, I do not know how to write my name is katakana. Do you know where I could translate it (knowing that the French pronunciation is different than the English one)

Thank you for your help!

You don't need your full name on a Hanako, just because it's supposed to be official. It is like your signature. You can choose to use your family name (which my European husband chose for his hanko).

My name is also very long but I only have my first name, in katakana, on my hanko. Haven't had any problems. I could have used my last name as well, but that was too long so I went with my first name.

And about not knowing katakana, you can have your hanko in Latin letters, I've seen people do that.

I have seen hanko with just initials (like "JFK") for people with looong names.

You actually do not need a hanko. While it is a nice item, everywhere I ever needed to give an official signature I could use just my normal signature.

Enjoy your life in Japan!

I only have my first and last name on my hanko, and it is registered, and I have needed to use it on some company documents, but that is pretty rare (a couple of times per year).
As for getting a kana representation of your name - type it phonetically into google translate and that will give you a version you can use.

Unless you are buying a house or a new car, you don't need a registered hanko. Your regular hanko (for banks or documents) can be whatever you like. Probably one of your surnames. However, nowadays, a signature is generally OK (again, unless you're buying a house or similar).