There are two "types".
One records locally to a security DVR (this can be a purpose-built machine or a spare computer put back to work just for this purpose). This version typically has you selecting the video capture parameters - record all the time, motion detection only... the amount of time the video can be available for review is based on what triggers the recording and the size of the memory (typically hard drive). After purchase/install, there's no other charges. I use Swann systems and they provide apps and secure remote viewing access for Windows and Macintosh computers, various tablets and smartphones. I can copy the video to a computer or smartphone if needed. When the recording storage device's hard drive fills, the oldest video is allowed to be overwritten. With the record trigger and hard drive space combo I have, 5 cameras' video up to 15 days is typical. Samsung, NightOwl, and many others make similar systems. Storing 6-24 hours of video will use a LOT of hard drive space. Fry's Electronics, B&H, Costco and others sell these Digital video Recorder or Network Video Recorder systems.
The other type sends the video to a file server somewhere on the internet - sometimes referred to as "cloud recording". Typically, the record trigger is by motion detection and each clip's length is limited to what the manufacturer allows. Remote viewing is possible via Windows or Macintosh computers, various tablets and smartphones. I have Ring products. Ring has a monthly subscription fee for stored video up to 6 months. If you pay for a year, there is a small discount on the subscription fee. This is similar to the Blink model.
What we don't know about your camera requirements:
Indoor or outdoor.
Night vision requirements.
Ability to run cable from the camra to the DVR/NVR.
Expectation of what is being captured to video.
Motion detection not good enough because...
Probably a couple more...