What day is today?
What date is today?
What is the date today?
What is the day today?
What day is your interview?
On What day is your interview?
Please check the validity of these questions and comment.
What day is today? – Possible, but more often people would say “What day is it today?”
What date is today? – Doesn’t sound very likely. Other ways of saying this, such as “What’s the date today?” or “What’s today’s date?”, are more usual.
What is the date today? – OK. In conversation “What is” would almost always be contracted to “What’s”.
What is the day today? – Seems less likely than “What day is it today?”
What day is your interview? – OK.
On what day is your interview? – Not common in conversational English.