A credit card allows you to borrow money when making purchases. The money isn't directly debited from your bank account at the time of purchase; instead, you are sent a bill every month for the sum total of your purchases.
The word debit means subtract and, as the name suggests, your debit card will subtract money from your account each time you use it.
A debit card has several of the advantages of a credit card in terms of convenience and reducing the use of cash and checks. Furthermore, you can use it as an ATM card as well, to withdraw cash from your account and carry out other ATM transactions.
However, you can't use a debit card to obtain credit. This can be an advantage since you can only buy what you can afford.
Furthermore, you don't have to worry about making regular payments or paying interest rates and penalties if you forget to make a payment. In that sense, a debit card is more convenient than a credit card.