When does hydrogen have a oxidation state of 1?

Hydrogen has an oxidation state of +1 whenever it interacts with a more electronegative element to form a compound (NH3) or whenever it forms an ionic-bonded acid (HClO4) or functions as a cation (NaHCO3).

Hydrogen has an oxidation state of 0 in its elemental form. (H2)

Hydrogen has an oxidation state of -1 whenever it forms and ionic salt as an anion. (LiH).