That might be because 'oda' means 'in that direction' or 'to that point', always indicating movement to a certain location. The word for simply 'there' would be 'ott'. There's a difference between the two words. If I were to say "Menj ott!", that could still be translated as "Go there!", but it would mean that I want you to walk there, in one place, or something like that.
"Ott megy a kutya." - The dog is walking there. (~not here, but somewhere over there, there's a dog walking) "Oda megy a kutya." - The dog is going there. (TO that place; he has a goal in mind)
Not sure if I could explain it clearly.
At imperative mode, you always have to put the prefix after the verb, but not with declarative sentences:
Fordítsd le! (lefordítani) = Translate it! / Lefordítok = I translate it. Mondd meg! (megmondani) = Say it! / Megmondod = You say it. Repülj oda! (odarepülni) = Fly there! / Odarepülnek = They fly there. Adja hozzá/össze! (hozzáad/összead) = Add it! / Hozzáadjuk/összeadjuk = We add it. Menj vissza! (visszamenni) = Come back! / Visszamegy = He comes back.
(Sorry if I made some mistakes, I'm not native and I just try to explain what I understood).