Apples are the currency of the game.
There are many ways to obtain them, with the most common throwing a knife at them.
In game[]
While playing the game, apples will sometimes appear on some stages.
You can find either regular red apples, or "golden apples" (unlocked bonus at level 5), which are worth double as red ones.
Although apples are currency, they more specifically are apple slices, as slicing an apple gives you two.
By Generate Free Apples[]
You can obtain unlimited free Apples with this generator tool: https://knifehit-hack.club
By Watching videos[]
You can obtain 50 apples with each video you watch. However, the bonus "More apples in videos", unlocked at level 6 allows you to get more from watching a video.
By Free Gift[]
You can also get apples in free gifts. A free gift is available every 8 hours. The bonus "more apples in free gift" can add more apples from the gift.
By following Estoty and Ketchapp[]
You can also follow Estoty and Ketchapp on their facebook and instagram. Doing so will give you 50 free apples each, meaning you'll get 200 apples in total.