Do I have to pay interest with Apple Card?

It is similar to other credit cards. If you pay in full before the due date then there is no interest. Also see the following from: How to avoid or lower Apple Card interest charges - Apple Support

If you're experiencing financial hardship due to the COVID-19 pandemic, you can enroll in our Customer Assistance Program which allows you to skip your Apple Card payment due in April without incurring any interest.

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How to avoid interest charges

To avoid being charged interest, pay your monthly balance every month on or before the due date. You know you're paying enough if the payment wheel turns green or blue.

For example:

• You open an Apple Card account in June. On July 1, you get your June statement that shows your June balance.
• If you pay off your full June balance by July 31, you aren't charged interest on the June balance.
• If you only pay a portion of the June balance by July 31:
• You're charged interest only on the unpaid amount from July 1 through July 31. This amount carries over into August and you're charged interest on new purchases that you make in July from the date of each purchase. The total of these interest charges is included in your July balance, and you continue to be charged interest on the unpaid portion of your July balance.

Yes you will have to pay interest if the card isn't paid in time.

See https://www.apple.com/apple-card/ for information on Apple Card.