Are we allowed to touch the table with the racquet

I have seen in some matches , that the players touch the table with the racquet,  but the rally continues, but some of my friends , who go to classes for table tennis, are told by their coach that the racquet can't touch the table.

I am confused, so exactly what is the rule?

Hi Nimit,

The racket is definitely allowed to touch the table.  The only thing that isn't allowed to touch the table is your free hand.