A credit card is basically “plastic money” as it comes as a rectangular plastic card. Using a credit card is like getting a loan - you can make transactions using your credit card using the bank’s money. Keep in mind that you are making purchases on borrowed money until you pay it back later when you receive your bill. You can also pay off your bill gradually over time (along with interest).
The credit card issuer adds interest charges to your account, which you must pay along with the purchase amounts, but if you pay within the “grace period” or interest free period, then it won’t attract any additional charges.