WorldEdit is a donator only perk for Creative if you have the Backer Rank this will allow you to edit an area quickly. You begin with the command //wand which will give you a Wooden Axe. WorldEdit allows you to replace or delete thousands of blocks in seconds, helping you to quickly start and finish builds.
⎠Commands
//pos1 - Set your first position to where you are standing
//pos2 - Set your second position to where you are standing
//set - Set the entire region to one or more block(s)
//walls - Create a walls around the region
//cut - Removes the region and saves it to your clipboard
//copy - Saves an Item to your clipboard
//paste - Pastes your clipboard
//expand [Number] [Up/down/south/east/south/west/vert] - Expands the region in the direction
//undo - Undo your previous worldedit
//replace [FromID] [ToID] - Replaces a certain block in a region
//rotate [Angle] - Rotates a the selection
//flip [right/left/upsidedown] - Flips the selection
//brush [type] [ID] [1-5] - Paints using your choice of pattern
//sel [type] - Change your tool (This allows you to create Spheres and such)
//stack [amount] - Stacks your selection in the direction you're facing
//wand - Recieve the wand tool
//desel - Unselect your current selection