Augments can be accessed by going to the Zombies mode in Black Ops 6, selecting the “Weapons” tab at the top of the screen, and then pressing “Augments.” Here, you can equip Augments on every perk, ammo mod, and Field Upgrade. You can also access the Augment Research screen.

Call of Duty: Black Ops 6 Zombies is built around the collection (and spending) of Essence, which are the "points" that serve as currency for purchasing weapons, ammo, perks, and pack-a-punch upgrades around the map.