You will need a user name and an e-mail address for your account. The user name has to be unique, so you might won't be able to use your first choice if the user name is already in use. But you will be able to create more than one account under the same e-mail address.
The password will be created by the system and you will receive an e-mail with you user data after a successful registration.
The creation of a synchronization account is completely free. It's up to you if you want to use the additional functions.
Please don't use special characters or umlauts in user name!