The Boko Bow is a common bow found in Breath of the Wild. It has a base power of 4 and is typically carried by Red Bokoblins in and around the Great Plateau. It occasionally is used by Bokoblins that are on horseback, as well as Stalkoblins.
"A basic Bokoblin bow made of wood. It's made by taking any tree branch and just tying a string to either end, so don't expect much in the way of combat effectiveness."
Due to its rather weak power, the Boko Bow is only of major use very on in Link's journey. With a base power of only 4, along with the Wooden Bow, it is the weakest Bow that Link can acquire in the game.
Hyrule Compendium entry of the Boko Bow.