Wie is dein Vorname/Nachname? OR Was...?
Hi,
I have to fill in either WIE or WAS in the questions in the subject box above:
---- ist dein Vorname?
--- ist dein Nachname?
(I assume it is better to use Heißen in general --- here, however, I am forced to use this construction).
Are both options (Wie, Was) possible/ idiomatic/equally common?
Thanks for your help.

Question

Answer

That sounds more idiomatic: Wie heißt du?" (informal) or "Wie heißen Sie?" (formal).
That's possible as well: Wie ist dein Name? Wie lautet dein Name? 
'Was' is not really used.