Any credit card that claims to be a "no-interest credit card" or a card with "0% interest" is a card with a temporary period where your purchases are not charged with interest.
The interest-free period is usually a short period, typically for a few months up to a couple of years, and is often associated with a promotion. The length of this period is always outlined as part of the terms when you sign up, so ensure you read them and take note.
After this promotional period is over, any remaining balance on the card and any new charges you make will be charged with a standard interest rate.
A lot of these cards can also come with an annual fee that may be discounted or waived during the 0 interest promotional period or another period. This will be charged once this waiver period ends, so make sure you know the ongoing charges.
While the no-interest promotional period is often only offered with some cards as an introductory offer, credit card holders can use this to reduce their debt by paying as much off as possible during the no-interest period.
Not all cards will offer a no-interest period, and you should understand the product disclaimer details that come with credit cards.