Use an anvil
Place the damaged bow and another bow in the anvil
Combine them to repair durability
Use an anvil
Place the damaged bow and string in the anvil
Repair the bow with materials if available in your version/mod
Use a grindstone
Place the bow in the grindstone to remove enchantments and repair by combining durability through crafting instead
Craft a new bow
Use the crafting grid with 3 sticks and 3 string
Use Mending enchantment
Gain experience while holding or wearing the bow to repair it automatically
Use Unbreaking enchantment
Reduce durability loss to make the bow last longer