There are four main types of computers: desktops, laptops, tablets, and smartphones. Desktops are stationary PCs that are typically larger than laptops and not portable. Laptops are portable computers that can be powered by batteries and have integrated keyboards and screens. Tablets are portable touchscreen devices that are typically larger than smartphones but smaller than laptops. Smartphones are mobile phones that have more advanced computing ability than basic feature phones and include functions like internet access and apps.