You must meet certain requirements to enter Denmark, even if you are not required a visa:
The purpose of your trip to Denmark must be plausible and comprehensible.
Your passport should be valid for at least 3 months beyond your stay in Denmark.
You must be able to finance your own living and travel costs.
You must hold a confirmed return flight, to prove that you are prepared to leave Denmark before the duration of the permitted stay ends.
You must have travel health insurance for the whole duration of your stay in Denmark.
You must not pose a threat to security or public order.