The problem in your code is that your code returns a character, instead of the pointer to it. The return type of the function suggests that the function returns a character. Hence, you need to revise its signature into char *copyStr(const char *str).

Another problem is that the return value dereferences the pointer newStr, making it return the value pointed by newStr at the very end of the execution of the function. You need to return newStr instead of *newStr.

Also, this might not affect the result of the function, but the one point I want to point out is that the delete statement after the return statement has no effect. Moreover, since according to the description about the function, the caller will use the C-string returned by the function. Deleting it would make it impossible.

In conclusion, the revised version of the code will be like...

char* copyStr(const char* str)
{
  char* newStr =  new char(20);
  for (; *str != '\0'; ++str)
  {
    *newStr = *str;
  }

  return newStr;
}

I also want to suggest to make the function take the length of the str as additional input, and dynamically allocate a memory space according to the length - which can be ignored if you assume that the input string will be less than 20 bytes in its size.