Do i have to fill out any additional information if i served in the military last year? if so how do i do this?

In the Personal Info or My Info section (whichever one your product has) after you enter your name, indicate that you served in the military (where exactly varies somewhat from product to product).

Once you have indicated that you served in 2020, then you will be asked additional questions about your rank, what combat zone (if any) you were in, and so on.

When you enter your W-2 from DFAS, on the next screen when it asks about uncommon situations, be sure to mark this W-2 as active duty pay (if it was for active duty).

When you get to the state returns, some may not ask you anything but others may ask additional questions - just answer them.

Also, back in the Personal Info or My Info section, if you are active duty, enter your home of record as your state of residence, not where you happened to be stationed at the time. In this way, you will get the correct state return.

Did you see all this? Then you are probably in good shape.