Would equipment that is wrongly used by a person be considered as a systematic error or a random or both? I would say a systematic error because a person could don't know how to use a ruler and starts his measurement at points that are not zero. And as a result, he will get wrong consistent data. But i am not sure so please help. Thank you.
Well it entirely depends on whether it is consistent as you say but no it is not the equipment but the operator that is the source of error (unless it is shipped with incorrect instructions, but again that is still a human error).
However, people are not static. Despite strong evidence to the contrary, they do have a capacity to learn, change and act in unpredictable ways and thus cannot be considered "consistent" and, as such, sources of systematic error. Humans are not a function of state. There are correlations, eg employee performance around contract renewal time, or the rise in grandma deaths during exam periods, but these are still in keeping with humans being random errors.
This is not an error. This is a mistake.
An error, in measurement theory, is an inescapable uncertainty due to the apparatus and the person using it. It may be random, varying between measurements, or it may be systematic, applying to all measurements.
Statistics provides tools to handle these uncertainties: combination of errors, chi squared, and so on.
But if you write down numbers in the wrong order, or interpret millivolts as volts, or add the date into the cash-received column, this is not an uncertainty but a mistake, and statistics cannot accommodate it (though it may provide tools to find it.)