very... veryy dumb question.

I am applying for my first cc via ringgitplus, will be getting the MBB 2 Gold.

Already have a MBB savings account

I come from a family that only uses cash so really need to research this by myself.

My question is,

interest rates are only charged on amounts that you don't pay back within the calendar month is it?

If i.e. today I pump RM50 petrol, and pay back that when the statement comes, I don't need to pay any interest or service charge? Assuming it is an annual fee free card.