 To get more inventory space within Hogwarts Legacy, you need to complete the Merlin Trials. These open up around that 15th main mission called the Trials of Merlin. Once you have completed this mission, you will see icons then appear on your map. These require you to have mallow sweet leaves. Now these leaves you can purchase from the Magic Leap vendor within Hogsmeade, but you are best once you can to buy the seeds and grow your own within the room of requirement. When you start completing these Merlin Trials, you will earn yourself more inventory space to hold more gear. Guys check out my channel for more Hogwarts Legacy.