Deductions & credits

I am an American citizen and have been living in Japan since 2019. Being a sofa member means I am employed with the United States government, I am paid by the United States government. My wife is a Japanese citizen who has never lived in the United States and she works for her family company here in Japan so all her income and taxes is from Japan. 

 

We got married this year and I was told the best way to do it is to file jointly as I can achieve a higher return that way. However she does not have an itin number and I know I need to submit a w7 for her to receive that. Where I work there was somebody that can do a certified copy of her passport to send in but I've been told one of two things. I can mail the w7 with the information with my current tax return in hopes of getting the itin or I just submit the w7 with a documents without filing my return at the same time. So my question is which one do I do?