A credit card and debit card are different things and are both safe if you use it correctly and don't lose it.
With both a credit card and a debit card you can disable the card by reporting them lost or stolen and the credit card company or bank will issue you a new card.
A debit card is where you use your own money to buy things and don't have to pay it back. With a credit card you use the credit "the loaned money" to purchase things and you pay back the balance you used on your credit card with interest.
If using a credit card it's best to not use your whole limit. Use what you can quickly pay back to keep your credit rating up and have a good credit score.
Using too much credit can hurt your credit score.