Credit score is based on how well you pay your credit card bills. Say you go to the store and buy a shirt for $10. At the end of the month you can pay the
minimum ($2) or pay the whole $10. If you pay the minimum then you’ll get charged interest. Say interest is 2% and you pay the minimum and don’t charge anymore to your credit card. Next month instead of paying $8 you’ll be paying $10. This makes it easy to slip into debt and debt makes for a poor credit score.
With a poor credit score you can’t apply for a loan for a car or a home.