The phrase "certain types" is an ambiguous term that can be used to describe a variety of things depending on the context in which it is being used. Generally, however, when someone says "certain types," they are referring to specific individuals or groups who exhibit certain characteristics or behaviors.
For example, if someone were to say "certain types of people love adventure travel," what they mean is that there are some individuals who have a preference for travel experiences that involve risk-taking and exploration, such as hiking through rugged terrain, white water rafting, or bungee jumping.
Similarly, if someone were to say "certain types of businesses struggle with cash flow," what they mean is that there are some companies that have difficulty managing their finances effectively and consistently experience problems related to money management such as delayed payments from customers or high expenses.
Overall, the phrase "certain types" can be used to describe a wide range of individuals, behaviors, or situations depending on the context in which it is being used.