Use a grindstone
Place the enchanted item in one input slot
Take the output item to remove the enchantments
Or use a crafting table with another same item to combine durability, but this does not remove enchantments
Use a stonecutter or smithing table only if the item type supports those actions, not for disenchanting
In Creative mode, replace the item with a non-enchanted one
On Java Edition, use commands to remove the item and give a new one without enchantments
On Bedrock Edition, use commands to clear the item and give a new one without enchantments