No more land border
Denmark is part of the Schengen agreement, which eliminated border passport control between Schengen countries in Europe. This means you no longer need to stop or show your passport when travelling between Denmark and Germany or Denmark and Sweden. You must still have your passport with you, however, when travelling in Schengen countries as a form of identification.
The following countries are part of the Schengen Agreement:
Denmark, Sweden, Norway, Finland, Iceland, Germany, Austria, Belgium, Holland, Luxembourg, France, Spain, Portugal, Italy, Greece, Estonia, Latvia, Lithuania, Malta, Poland, Slovenia, Slovakia and the Czech Republic.
There is a passport control when entering Denmark from a country outside the Schengen area and some nationalities need a visa to enter Denmark. You can check visa requirements for your country at the Danish Immigration Service website.