Pillowcases were invented to keep the pillow clean and prevent them from smelling. First, pillows were made of pure cotton, which is known for its liquid absorption properties and smells faster. For long periods of time and due to continuous absorption of sweat and other fluids; the pillow starts to smell. Pillowcases are also made of cotton and they absorb sweat; but they are easier to clean and faster to replace. Even after the invention of fabrics and their use in making pillows, pillowcases are still used all over the world for the same purpose.
Pillowcases have a huge number of patterns, as they can come with a set or be sold separately. If they come in a set, they will of course have the same design as its set. The separate pillowcases have many patterns and colors, they are available in solid colors or with paintings and drawings. There are pillowcases that can match other sets, which is good if you need to replace pillowcases without changing the whole set.
There are many standards for pillowcase sizes, and they all depend on the set and bed they are to be applied to. There are many sizes to suit all bed sizes, king size, queen size and twin. Each bed size has its standard pillow size, which is the main measure of the size of the pillow case. The main material for pillowcases is cotton, for its ability to absorb sweat and liquids. But recently, some other additions have been made to the pool of materials, such as fur; used in colder areas for more heat.
Every pillow needs a pillowcase, even if it was not in a bed. Some pillows are used on sofas and chairs, these also need pillowcases to prevent them from becoming stained or wet. The variety you find in the design and the material in the pillowcase is great, it gives you the chance to find exactly what you are looking for. There are also many online directories for well-known pillowcase retailers. You can also go through this.