INVENTORY lists your inventory. This command can also be abbreviated by typing IN or INV.
You may only hold a certain number of items in your inventory. To increase the number of items you can carry (with a maximum of between 36-39 depending on your class) wear +dexterity (dex) equipment. You may also place your items in bags, which only count as one item carried each, no matter how many items are inside. By typing SCORE you may see the number of items you are currently carrying as well as your maximum inventory. This inventory number also includes the items you are wearing. The line will appear something like this:
You are carrying 23/34 items (44 total/0 fined) with weight 135/500 kg.
The total listed (44 in this example) also includes items inside bags.
Likewise, you can only carry up to a certain weight limit. To increase your maximum weight allowed (maximum is between 500-925, depending on your class), wear +strength (str) equipment. As with the number of items you are carrying, you can also view your weight carried and max weight carried by typing SCORE.