These are also known as porcelain laminates. In a nutshell, it's where the dentist will bond a very thin sheet of porcelain to the outside of one or many of your teeth in hopes of improving your smile.
Nowadays, the materials are very strong and require little to no removal of sensitive tooth structure. It is important, however, to make sure that you have any cavities or gum disease treated prior to entertaining the idea of veneers. Once these problems are treated, the dentist can decide which laminates may be best for you.
Modern materials are so strong that they often require little to no removal of healthy tooth structure.
Talk to your dentist about what's the most appropriate for you. Again, if you want to change the overall shape, shade, size, or color of the teeth, laminates is a much more durable solution than bleaching alone.