Perks are abilities, passive or active, that allow your character to endure or perform more different actions. There is a great variety of Perks that can support many different play styles. You can access Perks by opening the game menu and navigating to the tab Perks.
To unlock Perks, you need Perk Points. Perk Points are granted when you complete certain tasks in the game. If you'd like to speed up the process or hunt for more Perk Points, take a look at the list in game menu > Challenges. This overview will show you which Challenges are available and how many Perk Points you'll earn upon completion.