Thinking means that a person can use his or her mind. Actually, all mental activities can be described as thinking. This includes, for example, thinking about a certain problem, such as a school assignment. Forming an opinion is thinking; being creative is also thinking. Remembering or dreaming are thinking processes. Thinking can therefore take place consciously or unconsciously. All thinking processes take place in our brain.
Intelligence is closely connected with thinking. Here, however, we tend to look at conscious thinking. If you are good at solving certain problems by thinking, you are also called intelligent. But if you have many vivid dreams, for many people this has nothing to do with intelligence. Nevertheless, it is part of thinking.