Flying at night requires training and a licence endorsment. Night flying under VFR is a great experience and much easier then you may think.
License / Medical:
PPL(A), LAPL(A) with valid SEP(land) or TMG classrating
valid aviation medical certificate (Medical)
basic instrument flight training
The theoretical training includes night flying related matters. Especially legislation, procedures, navigation and emergencies.
For the licence endorsment you will need to fly at least 5h at night. This includes minimum 3h dual instruction, 1h cross-country, including one 27NM(50km) cross-country flight and a minimum of 5 solo full-stop landings.