Containers come in many different sizes some ranging as small as a couple of inches across and a few inches tall in height, to huge, being several feet tall and several feet in diameter. These containers can be used just about anywhere, with the smallest ones being perfect for a tables-escape and the largest ones being appropriate for a very big landscape. So any container that you choose to use for garden plants should absolutely have a drainage hole in the bottom. So you might find something like this only has one hole, and something like this plastic pot might have several. But it's essential for the health of your plants that your container must have good drainage and therefore must have drainage holes in the bottom.