What Are Support Gems?
Support Gems are special socketed gems that modify or Path of Exile 2 Currency enhance the behavior of your active skills. They don't deal damage on their own, but instead alter how your main skill works—increasing damage, adding effects like projectiles or AoEs, modifying cost, and more.

Examples:

Added Cold Damage Support – adds flat cold damage to attacks or spells.

Multistrike Support – repeats melee attacks multiple times quickly.

Chain Support – causes projectiles to chain to additional targets.

Key Change in Path of Exile 2: Skill Gems in Weapons
In PoE 2, active skill gems are socketed directly into weapons, and support slots are unlocked based on weapon type and progression. Each weapon can have multiple built-in support slots that modify the active skill.

This changes the flow of gearing:

Your main skill is tied to your weapon

The weapon's support slots dictate how many supports can be active

You still insert support gems into those support slots—but they’re part of the item, not the armor.

This leads to buy POE 2 Exalted Orbs :

Fewer gem-swapping issues

Simplified gearing around key skills

Incentivized weapon crafting