There is no direct requirement in the ISO 13485:2016 that cover inventory management. In requirement 5.1 Management commitment is stated that management must ensure the availability of resources. Furthermore, in 6.1 Provision of resources is stated that top management must determine and provide resources needed to implement the quality management system and to meet applicable regulatory and customer requirements.
Inventory management usually considering to determine the vital stock levels. Following steps can be used to control your stock levels: establishing levels of operating stocks based on consumption/rate of usage; maintain periodically stock usage reports of each item kept in the store; establishing quantity, lead time, and availability of each item supplied on the market; keeping a record of all non-stock items received from suppliers, returned to suppliers and issued out to users.
Of course, as inventory management important is to have under control shelf life of both raw and packaging material and final goods; to follow the FIFO (first in first out) or FEFO (first expire first out) principle, which you find most useful for your type of production.