WHO lists here ICD guidelines and tools for cause of death recording and reporting.
Implementation of the ICD for mortality further requires establishing an infrastructure for finding the dead person (civil registration), recording, reporting and storing information, information flows, quality assurance and feedback, and training for classification users working with the input or output of data.
In the page, you can find WHO ICD-11 Mortality tooling "International form of medical certificate of cause of death" and "ICD-11 Reference guide", and WHO Interactive self-learning tool