Depending upon the number of turns in the secondary winding, the transformer can be called a Step-up or a Step-down transformer. The main point to be noted here is that there will not be any difference in the primary and secondary power of the transformer. Accordingly, if the voltage is high at secondary, then a low current is drawn to make the power stable.
Step Up
When the secondary winding has more turns than the primary winding, then the transformer is said to be a Step-up transformer. Here the induced EMF is greater than the input signal.
Step Down
When the secondary winding has a lesser number of turns than the primary winding, then the transformer is said to be a Step-down transformer. Here the induced EMF is lesser than the input signal.