Each camera needs power to operate. Some cameras use 12 volt DC and more expensive ones use 24 volt AC.
Both consume the same power but the 24 volt uses half of the current. It is better to use 24 volt when connecting a large number of cameras and when the distance between the camera and the power supply is long. 24 volt allows you to use thinner power wires than using 12 volt but the standard wires are good enough for both voltage options.

Individual power supply can be used for a single camera and central power supply for multiple cameras. You can have from 4 to 16 power outputs for cameras. Installation with central power supply looks nicer because of one power supply but the results are the same. If a single power supply breaks one camera will shut down until the power supply will be replaced while in central power supply all the cameras that use this power will be shut down.

You will need to make sure the power supply supports the number of cameras you want to install. Day night cameras consume more power than other cameras. This requires to have a stronger power supply (high amp) you can calculate the current consumption by adding all the current consumption of your cameras. Allow 0.3 amp for regular camera and 0.5 amp for day night camera and make sure it does not exceed the limit of the power supply.

Pay attention to the power supply voltage and make sure it fits your cameras 12 volt or 24 volts.