There are four major types of Female Genital Mutilation (FGM) as classified by the World Health Organization (WHO):

1. Type I (Clitoridectomy): Partial or total removal of the clitoral glans and/or the prepuce (clitoral hood).
2. Type II (Excision): Partial or total removal of the clitoral glans and labia minora, with or without removal of the labia majora.
3. Type III (Infibulation): Narrowing of the vaginal opening by cutting and repositioning the labia minora and/or labia majora, often creating a covering seal, with or without removal of the clitoral glans.
4. Type IV: All other harmful procedures to the female genitalia for non-medical purposes, such as pricking, piercing, incising, scraping, and cauterization.

These types have some subdivisions for more detail, but the four categories above cover the main classifications used globally.