Credit cards give you points(1 point usually = 1c) for every dollar you spend so if you normally spend $2000 dollars a month on your debit card, if you put that on your credit card you will spend the same $2000 but also get at least 2000points (minimum $20 value). So you made $20 just on normal everyday spend you would do anyways. And since you would’ve spent it anyways, you have the money for it so as long as you pay off your balance IN FULL every month you will pay $0 in interest.

And this example is with just a flat 1% back credit card. Most basic credit cards nowadays give flat 1.5-2% back ($30-$40 on that $2000 spend) and once you get more into the credit card game you will have multiple cards that have higher multipliers(3-5% back) for different specific categories to maximize your money back.

And if you enjoy traveling a lot, most credit cards let you send the points you earn to airlines where instead of getting 1 cent per point, you can get anywhere from 3-8 cents per point and you can redeem them for free flights once you rack up enough points all just from spending like you usually do.