Destiny 2: 10 Things You Didn't Know You Could Do
5. Get Exotic Engrams From Heroic Public Events
Every time you roll up to a public event, it can be one of many types. They all start at a basic level, but if you and those guardians around you do certain things over the course of the event, you will unlock the Heroic version. The Heroic version is going to land you more loot in the end, and it will also give you a better change of snagging an exotic engram.
So, when it comes to activating the Heroic event, it's actually quite simple: you just need to know what to do. For instance, when in the glimmer drill public event, if you destroy three glimmer nodes that spawn over the course of the event, the Heroic variant will activate.
For the Walker public event, you must deactivate all three force fields containing the scorch cannons. Each event has some small task you need to complete to transition into the Heroic event.
As long as you have the Guardians there to help you, always go for these Heroic variants. They will give you the most loot, which will help you level up faster, but that increased exotic chance should be enough to make you want to do it every time.