Good is an adjective and well is an adverb. Many people, including many native speakers, incorrectly use the adjective form good, rather than the adverb well.
Examples: I did good on the test. INCORRECT! - Correct form: I did well on the test. She played the game good. INCORRECT! - Correct form: She played the game well.
Use the adjective form good when describing something or someone. In other words, use goodwhen stating how something or someone is.
Examples: She is a good tennis player. Tom thinks he is a good listener.
Use the adverb form well when describing how something or someone does something.
Examples: She did extremely well on the exam. Our parents think we speak English well.