Two types of digital camera batteries are used. A proprietary battery is a unit that only fits one or a few digital camera models. Such batteries usually are square or rectangular in shape, and they're rechargeable.
An alkaline battery is a mass-produced type of battery that you usually throw away after use, such as a cylindrical AA or AAA battery. Such batteries have many different uses for consumer electronics devices.
Digital cameras typically can only use one type of battery.