REST operations support path, query, form, and header parameters. You can pass path and query parameters to an operation by appending them to the request URL. Header parameters are used to pass and receive information in the HTTP envelope containing the message body.
Path parameters can be applied only at the root level. They apply to all operations and cannot be defined per operation.
Query parameters can be applied both at the root level when they apply to all operations or they can be defined per operation too.
Header parameters are defined per operation and per direction. Request headers are separate from response headers.
Form parameters are applicable to POST, PUT, and PATCH operations only. They must be defined at the operation level only and cannot be defined at the binding level.