A veneer is a thin tooth colored material which is placed over the natural tooth to mask the underlying enamel either to improve aesthetics or to protect the enamel.
Veneer can be placed either on a single tooth or multiple teeth which are fractured or dicolored, where the patient is concerned about gaps in between front teeth, where the shape of tooth needs improving and in some cases, where teeth need straightening.
The two main types of materials used to fabricate veneers are composite and porcelain.
Composite veneer may be either directly placed on the tooth or indirectly fabricated in the lab and the porcelain veneer is only fabricated in the lab.

Your dentist will need to make an assessment of your oral health before recommending veneers. In order to make your veneers last long, you will need to maintain a good oral hygiene and also have 6 monthly check up and clean with your dentist.