How do I check if I am registered to vote and my ballot request was received so that I'll receive an overseas ballot?

You should always verify with your Local Election Official (LEO) that you will be receiving a ballot. After you send in your Federal Post Card Application (FPCA), call or email your LEO to verify they received your form and will be sending a blank ballot to you. The contact information is in the Instructions with your completed FPCA as well as here

Alternatively, most states provide a website where you can check to verify your voter status, but it is not always up to date. You can find it by searching for “[state] verify voter registration.”