The title, "Civvies," is slang for civilian clothes, and that small word sets the poem's whole tension. The speaker describes "a night vision / of things after the war": a dream, or perhaps a waking imagining in the dark, of what comes once the fighting stops. It's a hopeful picture on the surface, since the war is over and people can change out of their uniforms.
But the second stanza complicates that. "Other places call / out of uniform" can be read a few ways. Perhaps other places, other lives, are calling the speaker away from the soldier's role. Or the phrase may hint that the call itself is strange or unsettling, since a uniform gives order and identity, and taking it off means facing who you are without it.
The mood is quiet, uncertain and a little dreamlike. The short lines and the lack of punctuation leave a lot unsaid, so the feeling of relief mixes with unease. The poem doesn't say whether the future it imagines is a comfort or a worry, and that open question stays with the reader.