A single item (element, wire, wire corner) or a collection of items can be cut, copied or deleted from the circuit. Cutting item(s) removes them from the circuit and puts them on the clipboard. Copying item(s) make a copy of them on the clipboard. Items on the clipboard can then be pasted into the circuit they were taken from or into any other circuit. Deleting item(s) simply removes them from the circuit with no change to the clipboard.
To cut, copy or delete a single item, move the cursor over the item (it will turn pink when selected), and click the right mouse button. To cut, copy of delete several items, first select them, then click the right mouse button. A menu will appear with several options, three of which are cut, copy and delete. Simply pick the desired option.
Another way to cut or copy selected items is to type ctrl-X or ctrl-C respectively. You can delete selected items by hitting the "delete" key.