In Crucible, you increase your character’s stats by leveling, which you can do by taking out enemy players or the local NPC wildlife. You do this by collecting essence following each kill, and by completing objectives for the game mode. But you can augment and increase select stats of your character by locating amplifiers scattered over the match.
Amplifiers are unique structures in a Crucible match that will modify your character’s stats. For example, if you find a medkit amplify structure, you can interact with it to increase the number of medkits your character can hold during that fight. You can also do this with health and damage.
You can find amplifying stations by opening up your map screen and finding the icons. These structures are available for a limited time. You can click on your map to ping it to see if any of your allies are closer to it. These structures randomly spawn during the match.
You need to make your way over to them and interact with them before they disappear, and it takes a few seconds of standing in front of the structure for the amplifying to take effect. For the rest of the match, you will have this benefit.
If they reach it for you, they can secure the amplify, and the amplifier’s effects go to everyone on your team. It might be a good idea to have only one player go to secure it while the other work on the objective. These can easily tip the match in your favor, just as much as leveling up does.