Cremation was associated with Pagan practices in ancient Rome and Greece, which contradicted the Christian view of respect for the human body in life and in death. So for a long time Catholics were strictly forbidden from being cremated. Pope Paul VI reviewed the matter in the light of the prevailing cultural climate of the mid-20th Century, and decided to lift the ban on cremation, and to prohibit it only when, in the words of Canon Law, "it is chosen for reasons which are contrary to Christian teaching" (Can. 1176:3).
In summary, then, the Church permits cremation, provided that it does not demonstrate a denial of faith in the resurrection of the body (Catechism of the Catholic Church, 2301).
If you choose to be cremated, the Church teaches that your remains should be treated with the same respect as the decomposed remains of a body, and should be buried or entombed in a suitable place for commemoration of the deceased. This excludes the scattering of ashes.
Crossroads photo by Vladislov Babienko on Unsplash