You don't have to guess. There's an ordering of your names on your ID.
Use that. I'd be surprised if if is different to the one used by your country's revenue service.
If the taxman in your country both knows who you are and has a name for you, that's the correct name, regardless of whether unspoken rules about given/family/calling names exist or not.
Use that. I'd be surprised if if is different to the one used by your country's revenue service.
If the taxman in your country both knows who you are and has a name for you, that's the correct name, regardless of whether unspoken rules about given/family/calling names exist or not.