Is it correct to fast Six days of Shawwaal and missed fasts of Ramadan due to menstruation with one intention?

 Combining fasts of Ramadan and Shawwaal with one intention?

That is not valid, because fasting the six days of Shawwaal can only be done after fasting Ramadaan in full. 

Complete Answer:

https://islamqa.info/en/answers/39328/it-is-not-valid-to-combine-making-up-missed-ramadaan-fasts-with-fasting-six-days-of-shawwaal-with-one-intention