If your state of legal residence is MO, and you were stationed outside MO all year, and your only income for 2018 was your military pay, then you're not required to file a state tax return in either MO or GA.
Since you already filed a GA return by mistake, what you'll have to do now is file an AMENDED GA return, showing zero GA income, in order to receive a refund of the GA taxes you paid. Note that an amended return must be printed and mailed; it can't be e-filed.
https://ttlc.intuit.com/questions/4667233-how-do-i-amend-a-2018-return-in-turbotax
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
