Most materials are not magnetic, but some are. A magnetic material can be magnetised or will be attracted to a magnet. These metals are magnetic:
Steel is mostly iron, so steel is magnetic too.
A bar magnet is a permanent magnet. This means that its magnetism is there all the time and cannot be turned on or off. A bar magnet has two magnetic poles:
We say that opposite poles attract, and like poles repel.
How can you test if a piece of metal is actually a magnet? Seeing if it sticks to a magnet is not a good test, because unmagnetised iron, steel, cobalt and nickel objects will also do this. So you can only show that an object is a magnet if it repels a known magnet.