As mentioned above CDHDR (which has user id option) and CDPOS can be used. But for data to be stored here, ' Log data changes' have to be checked. Check this document that guides you on the steps to be taken to enable logging data changes.
You can also try transaction MM04, which will display all the changes in the material.
Also, there is an option to track all the changes in the Material master by using "Engineering change management".
In ECM you generate an "ECR" with Tcode CC01 and assign the object (material number that needs to be tracked for the changes).
Later in MM02, provide the ECR number in the initial screen. All the changes in the material master will get tracked.