Depends on what shape you want it to assume later. There are various patterns that an apple tree can be trained to follow. Those on fully dwarfing rootstocks will often not be able to grow as free standing specimens, since the small root system cannot support the eventual size of the top. Otherwise, any of them can be grown with minimal pruning as one would manage on ornamental crabapple tree. If you are not after maximum production and you have chosen a locally adapted cultivar there may not be much need for diligent pruning. Here fruit trees with a blanket of rotting, unutilized fruit beneath them are a common sight--plenty of production for most people can often be had without intensive management.
Google is your friend ;-) http://gardenaction.co.uk/fruit_veg_diary/fruit_veg_mini_project_september_2d_apple.asp
