My wife and I are both military. I am in the states and she is stationed in Korea. If I file out taxes jointly online, will there be a way she can sign as well?

When you e-file, there is no physical signature.   You sign electronically by entering your 2021 AGI or PIN.  Assuming you have your spouse's agreement to file jointly, you can enter that and e-file.  Your 2021 AGI is on line 11 of your 2021 Form 1040.  If you filed a joint return for 2021 that amount is the same for both of you.