Some abilities grant charges of Inspiration.
You can spend 1 charge of Inspiration as a Free Action on your turn to gain Lesser Healing.
You can spend 1 charge of Inspiration as a Free Action at any time to gain a +2 Bonus on a skill check that takes less than 1 round to complete, a saving throw, or an attack roll. You can only spend 1 charge of Inspiration in this way per skill check, saving throw, or attack roll. You can spend the charge of Inspiration before or after you roll the die.
You can spend 1 charge of Inspiration as a Free Action when you make a damage roll with a non-Autonomous action or ability to gain a +2 Bonus to the roll. You cannot gain this Bonus if you used a charge of Inspiration to gain a Bonus on the attack that is dealing this damage, nor can you gain it on a damage roll for a Persistent Damage effect.
Charges of Inspiration last until the end of the current combat. They cannot be generated or used outside of combat.
You can only hold 1 charge of Inspiration at a time; any charges you gain beyond that number are lost. Some Keystones grant the Boundless Inspiration ability, which increases the number of charges of Inspiration that a character can hold at once.