how to use these two SQL_CALC_FOUND_ROWS, FOUND_ROWS in database? Is these are Columns in table?
No these are not columns. You can use them as it is. You don't have to change these two keywords.
Actually, if you want to return any number of rows without running the statement again, then there is a need of SQLCALCFOUNDROWS keyword with select statement. And the second keyword FOUNDROWS returns a number indicating how many rows the first SELECT query would have returned, i.e. it returns the total count.