Pruning, bending, and wiring techniques are all employed when making an espalier. Of course an informal espalier is easier to achieve than a formal one with a rigidly angular or symmetric pattern, but many designs are possible. There are also many different, specific techniques you could try, depending on the tree and the pattern you want to create. Detailed lessons in espalier are beyond the scope of a Forum thread. I recommend you first check out from your local library or buy a book on the subject. There are
many different books available. Of course, on-line videos can also be most educational, but you do want to know enough beforehand to distinguish between good and bad information.