Elemental Weapon Damage

Based on content found on stackexchange:

Each element is tied to a certain enemy faction. and their shields is that element. using the element on them deals bonus damage and helps take down the shields much faster.

• Fallen
• Key shielded enemies: Captains
• Susceptible to: Arc damage, signified by blue shields
• Found mostly on: Earth (but all over too)

• Hive
• Key shielded enemies: Knights, Wizards, Shanks
• Susceptible to: Solar damage, signified by orange shields
• Found mostly on: Moon  (Earth too)

• Vex
• Key shielded enemies: Hobgoblin, Minotaur, Praetorian
• Susceptible to: Void damage, signified by purple shields (exception: some Harpies have arc shields)
• Found mostly on: Venus

• Cabal
• Key shielded enemies: Centurion, Colossus
• Susceptible to: Solar damage, signified by orange shields
• Found mostly on: Mars

Most of the time you won't need the element to deal damage, but in a few rare cases (I've noticed one area so far with Vex Harpies with Arc shields that only take damage from Arc attacks).
Your primary weapon will always be Kinetic damage, none with elements have been discovered yet (if they do exist). Your special and heavy weapons can and should have an element. Preferably one of each element so you are prepared for any encounter.

Each subclass also focuses on a specific elemental damage:

• Kinetic: Kinetic is the base damage type and can be considered "physical" damage.
• Arc: This elemental damage type is related to electricity and has an area of effect. The Hunter:Bladedancer and Titan:Striker subclasses focus on Arc damage.
• Solar: This elemental damage type is fire damage and has a chance to ignite enemies. The Hunter:Gunslinger and Warlock:Sunsinger subclasses focus on Solar Damage.
• Void: This elemental damage type is related to gravity and dark energy. The Titan:Defender and Warlock:Voidwalker subclasses focus on Void damage.