Some religious communities may use churches belonging to the Danish State Church.
Other Christian communities are allowed to permanently use Danish State Churches for church services and religious ceremonies. The permission has to be given by the bishop.
A local church council may also give permission for the church to be used for non-religious purposes. This requires that the purpose for which you want to use the church does not conflict with the characteristics of the church interior. This also requires permission from the bishop.
If you want to explore the possibility of using a church, you should start by contacting the church.