Which of the following actions increases the quantity of an item in a storage location in GCSS?

The action that increases the quantity of an item in a storage location in GCSS is processing a post goods receipt. When goods are received and entered into the system, this action updates the inventory records to reflect the new quantity on hand. It is essential for maintaining accurate inventory levels and ensuring that the system reflects the correct amount of stock available for use.

In a supply chain management context, receiving goods effectively signifies that those items are now part of the unit's assets, allowing for better planning, resource allocation, and operational readiness. Processing a post goods receipt confirms that the delivery of goods has been completed and that they are now stored in the designated location.

This action directly contributes to enhancing the inventory quantity, which is crucial for unit supply operations in GCSS. Therefore, it is the correct course of action that aligns with proper inventory management practices within the system.