Call something inclusive when it's designed or inclined to include. An exclusive club might let you in, but an inclusive one will ask you to join, no strings attached.
Inclusive is an adjective with several meanings: It can be used to describe something that's broad or extensive, such as thorough, inclusive research project. Or it describes a group that's particularly welcoming to all kinds of people. And an inclusive range is one where the limits are included along with what lies in between: a survey of “20-40 year-olds, inclusive” tells us 20 and 40 year-olds were counted, too.