For Declaration of Conformity see Conformance mark
Type Approval or Certificate of Conformity is granted to a product that meets a minimum set of regulatory, technical and safety requirements. Generally, type approval is required before a product is allowed to be sold in a particular country, so the requirements for a given product will vary around the world. Processes and certifications known as Type Approval in English are generally called Homologation, or some cognate expression, in other European languages.
Compliance to type-approval requirements can be denoted by a third-party marking on the back of the product (e.g. ABS, TUV,UL, CSA), or by a Type-Approval certificate obtained by a manufacturer and kept on file. The CE mark found on the back of many electronic devices does not mean that the product has obtained Type Approval in the European Union. The CE mark is the manufacturer's declaration that the system/assembly meets the MINIMUM safety requirements of all the Directives (laws) applicable to it, and of itself, does not signify any Third Party involvement in the design or testing of a system/assembly. Many of the New Approach safety directives do not mandate third party involvement at all(e.g. LVD, EMD), and the ones that do (e.g. PED, MDD, ATEX) only require Notified Body (NoBo) involvement above a certain degree of risk category. When the risk category mandates this involvement, the CE Marking on the system/assembly will be followed by the NoBo number, which right to use is granted by the NoBo after the required design review, testing or auditing, as spelled out in the Conformity Assessment options of each Directive. See http://ec.europa.eu/enterprise/policies/single-market-goods/cemarking/about-ce-marking/index_en.htm. On the other hand, in China type approval is denoted by the CCC mark.
Type Approval is not a term confined to a particular industry. Type Approval requirements exist for products as diverse as marine equipment, mobile phones, automotive industry, or medical equipment. Type approval simply means that the product is certified to meet certain requirements for its type, whatever that may be.