HR practices form the foundational operations of HR and include the overall strategies to achieve our goals. HR activities are everyday tasks designed to implement the practices. Simply put, HR practices answer what the organization wants to achieve and why while HR activities address how.
For example, developing talent and future leadership is a good practice and providing a space for upskilling knowledge is one of the activities to enforce that practice.
Thus, international HR practices are the umbrella encompassing HR activities. For a fully functional HR, both these are crucial.