Beer and CO2 react with each other according to some basic chemical laws. The more surface area between the beer and CO2 the faster the beer carbs. The lower the temperature the faster the beer carbs. The higher the CO2 pressure the faster the beer carbs.
Different styles of beer "like" different levels of carbonation. Most ales have less carb then a typical pilsner. Carbonation preferences vary country to country. I've been served a lot of American beer that quite literally would be illegal to serve in Munich. Different people like more or less carbonation.
Lots of variables, lots of different goals, lots of ways to get there. No easy single answer to the question.