Fruits grow only at certain plants. You can pluck and eat them. But watch out: it normally takes several days until new ones have grown.

!4Plucking fruits
You can pluck fruits by simple using:
[$key_use] - gather fruits
If they hang too high, you can also shoot them down with ranged weapons from trees or palms and pick them up afterwards.

!4Planting
Fruits can also be planted in order to gain more of them. For some, you need good skills in agriculture. These can be increased by just planting other things.
For planting, take the fruits into your hand, point at the ground and use it by pressing [$key_use].