Voltage that must mark the battery

Hello everyone, my question is what voltage should the battery mark, and the alternator?
And how these data are measured.
Thank you.

It must mark minimum 14 volts with the engine on

Hello, how are you:
To check the battery, it must be at rest, I mean, without electrical activity as minimum 12h.
Then you measure the voltage with a tester and assuming that each element must have 2.1V, the total voltage would be 12.6v to begin with.
When starting the engine should raise the voltage between 13.5Vy 14.5 depending on the state of the battery.
I advise you to also measure the amperage and know more accurately the state of the battery.
All the best

With a multitester you put positive in battery and the negative of the Batteria negative, you must measure 12.5 OLTS, without taking out the tester, ask someone to start and not to lower to less than 10.5, once starting the engine you must raise the voltage to up to 14.5 and minimum 13.5