Each and every Pokemon has a special ability attached to them. You can see this ability along with a small summary in each Pokemon’s summary menu. These abilities can grant various powers, such as a type boost when the Pokemon’s HP is low, surviving one-hit knock outs, absorbing types while enhancing stats, and much more.
Some Pokemon can only learn one type of ability, while other Pokemon learn one of two possible abilities. The ability is determined the instant the battle starts for wild Pokemon or the instant a gift Pokemon is received. Once the ability is set, it can only be changed after using the very rare item “Ability Capsule;” however, this item doesn’t work with hidden abilities (more on hidden abilities below). Certain Pokemon may change abilities after they evolve, and there’s no way to avoid it other than preventing evolution.
Along with regular abilities found on wild Pokemon, there are very rare hidden abilities. Hidden abilities cannot be found by normal Pokemon in the wild. They can be found on gift or event Pokemon or sometimes found on Pokemon in S.O.S. Battles.