An HDD is a storage which you can find in many desktop computers and notebooks. It is a component, where all your content such as movies, pictures and documents stored. Internal hard drives come in two main sizes. 2.5 inch HDDs will suit notebooks and smaller devices but also in newer pc cases, while 3.5 inch HDD can be found in desktop computers. Consumer HDDs have up to 16TB of storage available. In 2020 this is the most affordable type of storage for your PC.