We recommend changing your initial PIN-code to your personal preference. Make sure you choose a number combination that is easy to remember, but complex enough not to guess (e.g do not choose your birth date or postal code).
For digital authentication, you need to choose a 4-12 digit PIN code (just like on a bank card). You will be using this for access to digital services and for authenticating your identity for security reasons in some services.
For digital signature, you need to choose a 5-12 digit PIN code. You will be using this to give digital signatures for documents and contracts, but also to confirm legal actions (such as bank transfers etc).