The range is the distance from the highest value to the lowest value. The Inter-Quartile Range is quite literally just the range of the quartiles: the distance from the largest quartile to the smallest quartile, which is IQR=Q3-Q1.

What is the difference between range and interquartile range?

While the range gives you the spread of the whole data set, the interquartile range gives you the spread of the middle half of a data set.

Is IQR one number or a range?

Interquartile range is a range, so a difference between third and first quartiles IQR = Q3 - Q1. So it is a single number statistic, so this is exactly how you report it.