Hi @Gele, let me see if I can help out here.
In order to hide your number for outgoing calls, please follow the steps below.
- Find and tap the Phone app.
- Tap the settings icon (three vertical dots) > Settings > Calling accounts.
- Tap the account that you want to hide the number for.
- Tap Additional settings > Caller ID > Hide number.
Let me know if that helped and please post any replies in English and it will be easier for me and other users to assist you. 
