White Balance

(Post processing) - If you can store your image in RAW format, go for AWB(auto white balance). This is good, if you don't have time check WB for each shot and you trying to take shots in different lighting conditions. You can always change WB in post processing.

(Preprocessing-Select)- You could select one of the built-in modes. For example, if it is daylight and there is lots of sunlight, chose Daylight.

(Preprocessing-Custom)-Use gray card. This is a little more involved and probably another day's topic. But you can search Google/YouTube and get lots of information. Unless you are a professional doing magazine covers, not many use custom mode.