Will my type tell me what I am good at doing?

The MBTI tool does not measure competencies or aptitude in the way a math test can measure your math skills, for example.

None of the MBTI questions is designed to determine how good you are at a particular task.

A lot of research exists about what careers people of particular personality types tend to enter, however, as well as about what tasks each personality type tends to enjoy.

INTPs and INTJs tend to like the theoretical work of science, for example, and ESFPs and ESFJs tend to enjoy tasks that involve helping others in concrete ways.

Thus, the MBTI tool may give you insight into what you enjoy. Often people who enjoy their work do better at it.