Change mobile number format

   NSMutableString *stringts = [NSMutableString stringWithString:@"9874563210"];
    [stringts insertString:@"(" atIndex:0];
    [stringts insertString:@")" atIndex:4];
    [stringts insertString:@" " atIndex:5];
    [stringts insertString:@"-" atIndex:9];
    NSString *str = stringts;
    NSLog(@"str: %@",str);