You should first pay attention to error message, what is Oracle trying to say here. Invalid identifier means the column name entered is either missing or invalid
Enter a valid column name. In Oracle database, a valid column name must begin with a letter, be less than or equal to 30 characters, and consist of only alphanumeric characters and the special characters $, _, and #. If it contains other characters, then it must be enclosed in double quotation marks. It may not be a reserved word.
You can also refer this to know more about the solution to solve this error.
Hope it helps you!!