You can inspire others in battle. A creature that has a Bardic Inspiration die from you can roll that die and add the number rolled to a weapon damage roll it just made. Alternatively, when an attack roll is made against the creature , it can use its reaction to roll the Bardic Inspiration die and add the number rolled to its AC against that attack, after seeing the roll but before knowing whether it hits or misses.
You can use your wit to distract, confuse, and otherwise sap the confidence and competence from others.
When a creature that you can see within 60 feet of you makes an attack roll, an ability check, or a damage roll, you can use your reaction to expend one of your uses of Bardic Inspiration, rolling a Bardic Inspiration die and subtracting the number rolled from the creature's roll.
You can choose to use this feature after the creature makes its roll, but before the DM determines whether the attack roll or ability check succeeds or fails, or before the creature deals its damage. The creature is immune if it can't hear you or if it's immune to being charmed.
You can use soothing music or oration to help revitalize your wounded allies during a short rest. If you or any friendly creatures who can hear your performance regain hit points at the end of the short rest, each of those creatures regains an extra 1d6 hit points.
The extra hit points increase when you reach certain Bard levels: 1d8 at 9th level, 1d10 at 13th level, and 1d12 at 17th level
You can inspire others through stirring words or music. To do so you use a bonus action on your turn to choose one creature other than yourself within 60 feet of you who can hear you. The creature gains one Bardic Inspiration die, a d6.
Once within the next ten minutes, the creature can roll the die and add the number rolled to one ability check, attack roll or saving throw it makes. The creature can wait until after it rolls the d20 before deciding to use the Bardic Inspiration die, BUT must decide before the DM says whether the roll succeeds or fails. Once the Bardic Inspiration die is rolled, it is lost. A creature can have only one Bardic Inspiration die at a time.