A classical guitar will make use of nylon strings, so if you would see some classical guitars that are being sold, you will see that they have nylon strings. If you would see some of the newer guitars that are being sold right now, you will see that some of the newer guitars will come with steel strings.
This means that the strings might be a little bit too strong for some fingers that are not used to playing the guitar. If you would base the differences on the sounds of the guitars, you will notice that the nylon string will usually have a mellower sound as compared to the strings of the new guitars right now.