What are some types of research?

There are many, many kinds of research. Quantitative (numerical) research is any research involving numbers, statistics etc... Qualitative research is any research that doesn't have to do with numbers. Maybe you are trying to figure out the personality types of people who usually buy body wash instead of bar soap. That's qualitative. Causal research is research into cause and effects. For example, what were the causes of WW1? Or what (if any) is the relationship between education and income?