Inference is using the information/data to conclude something. This will be a conclusion based on our best guess given the information.
Ex: You infer that your boss is rich because he drives an expensive car and wears nice clothes.
You infer your neighbour is rude because she never says hello or looks at you.
These are inferences/ best guesses based on what you get from the information available.
Maybe you are right in the 2 examples, or you could be wrong. Maybe your boss only has a nice car because he rents it and his clothes are not that expensive. Your neighbour could just be very shy and not rude.
You just infer based on the best you can do with the information you have.