Aim and target can mean the same thing. Or they can mean different things.
When they are used to mean something that you want to achieve/a result that you want to gain (a goal) they mean the same thing - "Our aim to sell 100,000 more phones this year." "Our target is to sell 100,000 more phones this year." - in both of these cases you want to sell 100,000 more phones this year.
Both words have other meanings too.
For example "to target (somebody)" means to single out somebody else for particular attention - you could be targeting them as a new hire for your company or because you want to have them killed (or lots of other things!)
If you say "My aim is true," that means that you can be very accurate when it comes to trying to shoot something to a particular point - for example to shoot a gun at a target (here target is a noun which means something to be hit) or a football at the goal.