Credit score is a number that is based on a person's spending and saving habits. It is often used by banks to tell if you should be able to pay back a debt (eg. a loan).
Most credit scores are between 300 and 850, where a higher value is achieved by paying back debts, and avoiding debts. It is calculated based on the information in a credit report, which shows how much the person has been spending and if they’ve made payments on time.