Refer to figure.
According to ICAO Annex 6, Annex 10 and Annex 14, there are two types of classification for approach operations, dependent upon the achieved minima at the end of the approach:

• Type A: may be either 2D or 3D operations; 2D will only have a lateral path defined for the approach operation where 3D will have both a lateral and vertical path defined for that operation. A Type A operation will permit aircraft operations down to a minimum height or altitude of 250 ft. All NPAs and Approcahes with Vertical guidance (APV) using Barometric altimetry are Type A approach operations.
• Type B: are 3D operations; a lateral and vertical path is defined and guidance along this path is provided either from GNSS augmented with SBAS (APV SBAS) or GBAS, or by a precision approach system (ILS, MLS).